Why aren't more people attracted to aviation? Well, there's attraction, there's finishing the rating (2/3rds don't), and there's retention post-certificate.
Well, according to my godkid, who gave up on flying once she discovered boys aren't always icky and gross (and now is getting perilously close to wanting the car keys), it's "not cool." To be more specific, the idea of flying is cool - being up in the air like a bird - but the "ancient" Cessna 172 I rented for her to get flying lessons as a reward for good grades was "So old it's not even retro. But not, like, old enough to be steampunk cool. It's just gross."
On the other hand, the ability to get out camping is "way cool" and fishing where there are no roads or crowds is "awesome" (although the lack of cell phone service for texting "really blows goats.") And air racing passes the cool test, as do acrobatics. (She wants to do that someday, "but mom'd kill me.") Currently her David Clark headset is plugged into the computer with an adapter to be a pretty good set of headphones for ignoring the world.
1. People don't get interested in something they never hear about or see, or can't approach.
I look at the airports I visited in the Lower 48, and though I hear a myth of golden age when kids could ride down to an airport, hang on the fence, provide scut work for rides, and ease into the world of flight, today all I see are sunbaked deserted ramps and locked hangars, with a few forlorn aircraft outside and FBOs with all the warmth and charm of a business lobby providing the only break in security fencing. If a kid wants to be 'like a bird', where exactly is an inviting entrance there? How often do you hear anyone who's not a pilot mention the airport or go there?
In Anchorage, Lake Hood actively encourages dog walkers and joggers with a small playground right next to transient parking, and Merrill's edges are groomed into a nice place with pullouts and a WWII memorial for people to come look at history, walk their dogs, play frisbee, practice guitar (I even saw a guy practicing violin once), etc. This is an awesome practice, not only because it provides more places for people to walk their dogs, but also because it provides an environment for positive interaction, and normalization of flying. If you're walking your dog where planes are always taking off and landing, then airplanes are 'normal'. If you see the guys coming in and out in their beat-up pickups and cars, you know, even if you don't talk to them, that it's not a "rich man's sport." Better yet, it also means that if a developer wants to move on an airport, there's resistance by the neighborhood nearby, because it's "our airport", and "Our Park" - they have something to lose. At Lake Hood, there's no fence - small children, college kids, tourists, and joggers can (and do) come up to talk to you (and try to cadge rides).
On a completely different tangent, this is also where the Red Bull Air Race (NASCAR with planes), is wonderful - it brings the excitement and speed, the fun and adrenaline and engines roaring, to the world. Reno Air Races are great for pilots - but the Red Bull Air Races are great for observers, and they sell the idea of aviation as an extreme sport to the world
(As a side note - the media does its level best to convince us aviation is extremely dangerous. That's terrible if we're trying to sell it an an alternative to your car. That's perfectly fine for extreme sports - all the spectacular wipeouts on skateboards ever shown have not dissuaded kids from picking up a skateboard or trick bike or snowboard themselves. Exciting and fun things are supposed to be dangerous - and for all the sales of snowboarding videogames, there are plenty of kids out on the slopes of Alyeska and Hatcher Pass with snowboards, too.)
2. People explore and excel to the limits of their imagination. If you want them to reach further than just a rating, you have to get them to dream bigger.
By this, I mean that when I walk into an FBO or a flight school in the lower 48, most are aimed at "become an airline pilot" - even the small mom & pops. (In Alaska, the large flight schools are often guilty as well.) Well, that's fine for people who have their heart set on being an airline pilot - but if they just want to learn to fly they only see this sterile vision of asphalt to asphalt, nosewheel only, in 35-year-old nosewheels, with a heavy emphasis on getting your instrument ticket right afterward. And the dream of flying like a bird doesn't measure up to the reality of $145/hr dual instruction. Worse, after the ticket, what's the motivation to stay in the air, paying $90/hr for a airplane with no shoulder room or cupholders? So it drops away for other priorities.
This is where, honestly, you all come in. That 80-odd page thread of "where did you fly today?" has some astounding photos, and some absolutely heartwarming photos. I've sent folks there, and watched them go from the vaguely bored of "Someone's vacation photos? joy." to "Wow, I want to fly there!" Because in the part 141 airline-pilot-creation, nobody ever told them that you can still land on grass and gravel, and that there are still tailwheels and farmer's fields and wilderness airplane camping strips. "Short-and-soft-field" is just some maneuver in the PTS, until we make it come alive in youtube and vimeo videos, in flickr photostreams, in blog posts and message boards.
If we can get people to dream of getting their own plane and taking it camping - if we can give them places to go, people to meet, things to see - then they are much more likely to continue flying after they've gotten their license. If the seaplane rating goes from a weekend add-on course because they wanted to fly but touch n' go's at their home port is boring to the means by which they get out and explore the country, they're going to continue flying floats. If the tailwheel goes from a five-hour add-on course to flying into wilderness strips for family camping, they'll keep flying tailwheel. If acrobatic goes from an unusual attitude training to "So, coming to next week's competition?", they'll spend time in the box getting the maneuvers down and finding joy in inverted flight.
3. It's not the money, it's the priority
You know, there was a study done on folks in a country who were holding their kids back in school because they were "too poor" to afford the school fees. And they are poor, and compared to what they make a week, school fees are expensive - about half a week's wages. But many of these same people, the study found, spent that amount every week in alcohol. And no few of the families had multiple cell phones in the family. If they were just sober for a week - or quit buying phone time - they could put their kids through school! The summary was "education is not a priority for the poor in this country."
I bought my plane working retail. Not a particularly hot retail job, and not making commission. Now, I paid $1000 a month for fifteen months, and it was harsh - no rental flying, no new clothes, very little eating out, no movies, no vacation getaways - but at the end, I own my plane free and clear, which is more than most folks can say about their cars. My godkid was perfectly capable of working her tail off doing odd jobs all over the place for cash in hand when we told her she had to finance half the school trip to Australia if she wanted to go - and she did it. So if it was important enough to her to find the money to learn to fly, I don't doubt that she would. Right now, music, makeup, and fashionable clothes are more important to my godkid than flying. Flying's more important to me, which explains why somebody sighs and rolls their eyes at my clothes when being driven to the mall.
Keep flying interesting places and having fun. Keep writing. Keep taking pictures and video. Keep talking to your friends. Keep inviting folks out. I don't have any other answers, yet.