Have read that every community, be it foodies, or science fiction fans, or horror film buffs, has two components- the casual, who tend to have a very low depth of awareness about the content of the field and make up the majority of the people involved in it, and the hardcore- who've seen everything, can tell you all about it, and make a tiny minority of the community.
It's these hardcore users that form the gatekeepers to the mainstream- not only will they be the first to try products, but they will also be far more harsh and negative to mediocre products than a typical user would be. (It's kinda comforting that the people who know everything about something I get excited about aren't keeping the best stuff to themselves and leaving me with the dregs, but rather the reverse). What these gatekeepers look for isn't usually all that different from what casual users look for- quality is quality.
The winner-take-all distribution can be really daunting, but when you consider how long each of these apps on top have been in existence at all (maybe a few years for most), then you realize that it's not so much luck that makes these top apps so much more successful than average, but that their content is just that much better from a market perspective.
The lesson here is, make a good enough product (something the market REALLY wants even if no one realizes it yet), and the market will promote you naturally. Some sort of "ASEO", if it's even possible, won't make a fart app into #3 on the app store.