As a once-and-likely-future vendor of transpilers, I think about this a lot. The TypeScript's and JSX's of the world are not chained to the back-compat firmaments the way languages and platforms are, and taking bets on them is something we should _culturally_ discourage. https://twitter.com/slightlylate/status/1351344411758583808

The ethical thing for transpiler vendors to do is to work themselves out of a job; to find the standard or platform vendor they can influence and get their improvements written into the system such that they can fade away. It's a dual failure when those bodies don't listen.

The CSS WG, e.g., only just took up hierarchical CSS *in 2020* after > 10 years of popular transpilers having it by default. TC39 is still doing things that aren't "putting TypeScript out of business", and I have no idea why.

Both sides should welcome that folding-in. Celebrating transpiler proliferation is itself an indication that a lot of things have gone wrong.

BTW, I think Babel has done better than most here. It's hewing a close line to the spec...the problem is its prevalence, rather than its qualities.