My understanding is games with microtransactions optimise for "whales", people who spend inordinate amounts of money. While the majority of users don't pay anything, or at most very little.
My understanding is whales make the mobile gaming industry the juggernaut it is, but without whales it would still be a sizeable market.
My mental image of it is looking at Apple when the iPhone was 2 or 3 years old, and today's Apple: its current size dwarfs the Apple of back in the days, but it wasn't some small also-ran company, it's impact on the whole industry was still pretty big.
AppsFlyer's data on this was interesting, while not straightforward to interpret from our angle.
My understanding is games with microtransactions optimise for "whales", people who spend inordinate amounts of money. While the majority of users don't pay anything, or at most very little.