Amazon got lucky that Mozilla gave up
Translation: "We used a nifty new language and had to hire an expert when the organisation sponsoring it threw in the towel. Good thing they didn't keep at it but take the language in some direction inappropriate for our uses, because then Klock might not be available to us."
I'll reserve judgement on the language itself, other than to say, whatever the merits of the borrow-checker concept, it seems to be almost as much like line noise as perl or TECO. At some point I'll learn enough Rust to form an opinion, but I'm afraid it's behind Erlang in the queue.
I'd prefer if the next language did not hail from the Anglosphere - every language from there (B, BCPL, Bliss, C, C++, perl, go, Swift) has lacked taste. Yet a succession of elegant things from other countries (Pascal, Modula-2, Simula-67, Ada, and probably if I knew them Erlang and OCaml) have sunk almost without trace. I quite like Python - guess what, it's originally from the Netherlands.
It's almost as though dominance of languages has little to do with their merits and more to do with what big American companies like.