The licensing concern is serious. And it's a serious concern if corporations are using Rust migration as a Trojan horse for undermining the GPL. These are political problems and it would be a shame to see these undermine the popularity of a pretty useful programming language.
The lack of Rust compiler support for older machines is a real concern, especially if we start losing access to the C/C++ versions of core libraries as distros stop including them or as developers stop supporting them. But older machines already need to run some pretty specialized versions of Linux rather than the mainstream distros, because this isn't the only place where new distros are moving away from long-term backwards compatibility, and everything is more resource hungry these days.
All the whining about "Rust people" though is a bit insufferable and off-putting. It seems like an issue of corporations setting the direction rather than a reason to resent Rust developers as such.