I don't think it's dumb, maybe overkill would be a better term. You want the stuff that is frequently used (e.g. the kernel, device drivers, etc.) to be fully optimized and totally bug free. There's no reason for it be 100% assembly. They could have just as easily written most of the UI code with C/C++ then optimized the lower level code with assembly. The work would get done faster and it would have more useful features.

Who in American industry is still doing basic research?

Mostly startups and universities.