Well, Deno devs did try to use TypeScript, and just ran into some challenges, and decided to throw the baby out with the bath water. I've seen this a lot in my 30yrs exp.: some developer/team runs into problems, gets frustrated, gives up, and decides the best decision is to remove some important piece rather than solve the actual problems.
The reason Deno is giving up TypeScript is representative of failure, and not an indication them wanting JS instead of TS. What they want is TS.
The rest of your reply is just stating some minor imperfections that are a billion miles from invalidating TS. And yeah, there's a place for JavaScript still, for small-scale tinkering, or perhaps even prototypes with only a few hundred lines of code. Any large scale project in JavaScript (not TS) is simply unfathomable to any modern developer worth his salt.
