This is great news. Microsoft is adopting/forking Rust. That means Rust will be supported for all eternity.
Just like Windows on ARM is supported for all of eternity! Or google anything, or any one of a million failed and dead projects. Cool that MS is using something Ruat based. In no way does that opinion lead to a conclusion of ongoing support.
Windows on ARM is probably fine. Windows Phone and the like eventually lost (losing? I haven’t kept up) support, but phones are traditionally a 2ish year supported device and then they’re not targeted (specifically in the Android OEM arena). Windows proper they have business clients and if they don’t support it for a reasonable amount of time, Microsoft is basically hosed. It is, I imagine, why once they decided to kill off older IEs everything prior to latest and greatest was killed at the same time: they had supported them for far too long and it required killing them all Off in one move.