You just named single player games only, think of the multiplayer games that are free to play but people pay through the nose for battle passes and skins etc. If the game is good enough and free why not throw the devs $15 for some stupid vanity item which doesn't actually level up your avatar in any way. 

I'm just a game junkie either way, I do err on the side of caution when dealing with f2p at the start but if it the devs do it proper justice then I have absolutely *NO* qualms with giving them some money for creating something worth playing. 
 

 I think GameFi is gonna be a big driver this coming cycle.