I write types everywhere. Without types, I'm in the blind. So yeah, don't look at motifs why some library maintainer has TS errors in their declaration files. I'm a full-stack TS developer, and I can count on my one hand fingers the times when some library had type problems. And if they had, I would fix them with my own declarations. But how do you code without types? It brings so much clarity to everything. Judging by your questions, you haven't worked with TS a bit. Or you like sensational HN titles, drawing in all the kids lol
I've been continuously frustrated by it - but the projects I'm working with are large, or leverage some more complicated dependencies. For example both ProtobufJS and Apollo can be very tricky.
I also do a lot of refactoring and improvement on these codebases, often updating packages, so perhaps I run into more issues more frequently than many. I accept that a lot of the time it can be smooth sailing, but anything tricky and it's a real time sink.