Can have it both ways
Hellwig doesn't want the code in his repo because he doesn't want to maintain it.
He also doesn't want it outside of his repo where somebody else will maintain it.
He says it makes kernel code harder to maintain.
The whole reason people are using rust in the kernel is because it makes also makes some kernel code easier to maintain.
If Linus doesn't move for acceptance then we will have an egcs situation - a separate kernel tree will be maintained and we will see which one the distros take.
Linus is smart enough to see that, is also smart enough to see the technical benefits.
Hellwig needs to think less about what his preferences and more about where the kernel is going to be in 10 years regardless of his position.
There are going to be rust kernels. He can influence whether or not they are called Linux.
But at least one of them will be based on Linux.