I'm sure the GNU people are working on this to make it work. The GNU project doesn't want to ignite massive forking efforts.
Their Hurd kernel is at least another decade away from being two decades behind.
Linux couldn't become GPLv3 even if Linus wanted.
Doing so would require the consent of all the developers who contributed code to Linux since it's inception.
But as you could probably imagine, some of the contributors are deceased now.
My guess is the LGPLv3 provisions in GLibc will make it possible.
Stand-alone userland software, such as BASH, will continue to be fine since they dont link with the GPLv2 kernel per say.