1 - are you saying this from experience? It’s all muscle memory. I can assure you there are former great shooters that can go LONG stretches of time and pick up a ball and not miss a beat. I know plenty of people that can. Do you think David Gilmour could play the guitar solo of “Wish you were here” after 10 years of not playing? The answer is he definitely could. Similar thing...muscle memory.
2 - Yes, it is harder to convert shots in a game, but not so much for free throws. They’re uncontested obviously, so the in-game atmosphere doesn’t play as much into it. Yeah, maybe he laces them in practice and has a mental block in the game. But until someone comes on here and says that, I’m just going with he’s not that great of a shooter. Because a lot of guys shoot great in practice and shoot great in the game. Fish was high 80’s in FT %, so accordingly to your logic, when he’s not in the game and well rested he never misses.