From a technical point of view, I'm not so sure. C++ still interoperate easier with C than Rust, if only because you can normally just include the headers and be done with it. (Although as the article says, there are some cleanup to do.)
Rust isn't being experimented with in the kernel because someone decided we should really add a second language. C++ interop with C doesn't matter when there's no reason to use C++ in the kernel anyway.
It's easy to make it compatible by not using fields called "class", or using #ifndef __cplusplus, most C library headers are actually like that. But not the Linux kernel because they refuse it.
That's why I'm saying that the choice is not a technical one.
I doubt that Linux headers give a damn about usability from C++ though.