Many mobile games are just thinly veiled attempts at monetization. Get people hooked, then start adding time-bound gates you can unlock, add PvP with loot boxes and multiple types of premium currency that’s hard to keep track of. Doesn’t matter what the game is about - you can do this to racing games, fighting games, gardening games, whatever.
That said there are still mobile games that are fun and genuinely good gameplay - I used to love Minigore too, after it was available on Android. But these are few and far between.