Then a few months ago I decided to write a TS project from scratch. For the record I have 18 years of JavaScript experience. What I found was that the biggest barrier to entry was configuring webpack to be "just right". Other devs on my team with similar level of experience would have their eyes glaze over when webpack came up and get annoyed. For good reason. It took me several days to get it to work right. The fact that the tsconfig has 20 options that can effect the transpiler and not have good docs is a problem. The fact that there needs to be two tsconfigs in a react native project that compiles down to web as a secondary build target is another problem. The fact that you need a very experienced dev to spend days configuring webpack is another problem. Finding information about the right configuration is like the blind leading the blind. Most search results on the topic are riddled with half truths and non sense. Many devs rely on a preexisting webpack config and if they do anything to mess it up they are many times completely unable to fix it.
Typescript is fine. I guess. The code produced is nicer. But having to rely on webpack is an issue.
I actually like TS but I wish I didn't need to transpile anything or have to bang my head against a webpack config for days. It's by far the biggest barrier to entry because while you're banging your head against it you're not writing code. And for none technical stake holders when you have nothing visual to show at stand ups that can create friction and make the engineers seem like they aren't doing anything.
So far at multiple companies I've had to configure webpack for extremely complex JavaScript based single page apps which took me literally months of messing around with it until it worked just right. And until it does work "just right" the non technical folks think you're wasting time.