A rewrite is not taking it "to the next level". It provides a new version in a new language that does the same things, and if things go according to plan, will have fewer safety issues. There's nothing that binds them to maintain any of these projects. Given Google's history, it's irresponsible to not consider long-term maintenance and other issues.

No, C and Rust definitely don't do the same things. If the project is open source, I don't see how any maintenance concerns are relevant - everybody can judge for themselves.

It's not that smart to mistake the purpose or specification of a program, with its implementation.

Anyway, if everybody can judge for themselves, then I guess it's cool to judge that giving Google an inch over many critical open source projects is a horrible idea.

You speak as if it's impossible for someone outside Google to maintain a project that isn't written in C++ or C...

Sure, nobody says you have to use their software. But don't claim that they don't give back or that it's purposeless.