I didn't say anywhere I have 30 years of experience with XML. What I said is, EVERYONE is familiar with the syntax. JSX is especially suited for expressing HTML because it is, in fact, almost HTML.
As to your other point - maybe. I'm not seeing anywhere near enough potential payoff to invest years into it, though. Also, I'd argue that makes it a terribly impractical language if you're interested in getting work done.
To clarify, I don't agree one needs years to become competent in clojure. But if one did, that just makes it a worse value proposition.