And it could be, that C is a language in decline and the linux team should consider it before it becomes the next Cobol.

If that possibility was real, wouldnt you want to care about it?

Imagine Linus Torvals gone and the kernel devs only consisting of highly payed full-time C-Dinosaurs from a few mega corps. And the entry bar for young enthusiasts being not just learning C but the linux kernel version of it. How much worth would the GPL then be?