>How do you discover quality games?
You can't because the discoverability is terrible and the various app stores just care about raw sales, not quality. So that means that devs who want to make quality games never get noticed and that's a major disincentive to produce such games. Mobile gaming doesn't have the tech press, steam-like reviews, etc other gaming has. Its a lot of impulsive buyers feeding a market that delivers crap because crap is good enough for them.
This is like asking where the chess table at a casino is. The casino and the people who go there have no interest in chess. They just want you to toss your money into a skinner box, which is what freemium games are.
Google and Apple could fix this, but prefer to lean towards the 'popular' discoverability than the 'quality' discoverability. I think they're wrong and have turned mobile into a ghetto in so many ways - its not just games, but obviously they prefer this method, which I imagine is more profitable. See the recent reports on how freemium games are powered by 'unicorns' who pay vast sums of money for in-game purchasing, all of which Google and Apple get 20-30% of.