They usually are free to play with predatory monetization mechanics. That was especially back in 2016 when thanks to these games, the mobile gaming revenue outpaced PC and console gaming revenue.
Shoutout to Slay the Spire, Balatro, and Slice & Dice. They all cost a bit (around 10€) but are excellent ports of the originals and among the best mobile games. Slice & Dice even started out as a mobile game and was ported to PC later.
Mobile very quickly turned into a race-to-the-bottom. When the market is flooded, any paid title has an incredibly difficult time standing out. So in order to get players in the door, you gotta make it f2p. And in order to maximize profits for a f2p game, you gotta employ all the worst dark patterns, because that’s what all your competitors are doing too.
And this has led to a feedback loop of consumer expectations. People understand that this is just what mobile is now, so people who want anything else have given up on mobile and are instead buying games on other platforms. Releasing a premium title on mobile is basically just trying to sell to the wrong audience.
capitalism and greed
