Sometimes I get the impression that other transpiled langs have npm + decent minification + decent non-minified compiled size, etc without having to wait for years.
Of course, this can be changed (and Clojurists Together can be instrumental)!
The npm ecosystem is absolutely massive, but 99.999% of it is irrelevant for most frontend development.
All that said, clojurescript is not necessarily the best choice for any given org. Mostly just saying there's nothing regarding the ecosystem that should hold you back.
The advantage is best-in-class dead code elimination, which is also why Closure was chosen; to distill the CLojurescript standard library into just the parts needed for a web page requires good DCE. Recently, other Js projects like Rollup and Webpack have gotten good DCE, but when Clojurescript was started, there were no other serious contenders.
Totally. The closure compiler, despite it's age, is the best Javascript optimizer/uglifier out there. Nothing else comes close. There are several top notch, maintained frameworks as well (re-frame/om)