As a person who has a number of relatively niche hobbies, I assure you that this is not true. There's a ton of simple things that can be build and will make an immediate difference in the lives of thousands. Watch the workflow any musician, videographer, machinist, etc - they're full of small, weird inefficiencies that AI hasn't really solved for them.

It's just that you can't build a billion-dollar company around it. No one could go to a VC and say "we're going to be the Uber of focus stacking and dust removal for microscopy" or "we're the Uber of aligning the beats in two audio tracks".