As much as I prefer this model that actually isn’t what creates engagement and retains players over several games and years. They don’t do it because it’s fun to make predatory things. They do it because it makes them heaps of money. If it didn’t work, they wouldn’t do it. That’s the sad truth here.
Re: hats and paint jobs…hats dominated TF2 for how long? There was a black market and widespread scamming for cosmetics, that’s how nuts it got.