I partly agree, but there are puzzle heavy games with throwaway plots and people do mention they like games because of the puzzles, so I thought my observation

I partly agree, but there are puzzle heavy games with throwaway plots and people do mention they like games because of the puzzles, so I thought my observation was non-obvious. People still talk about the death of adventure games being caused by moon logic puzzles, but I don't hear people mention that part of the problem is the design space of item based puzzles is more limited than you'd think (I mean non-magic, non-NPC stuff) and has been mostly explored.