That's a completely separate issue. The trusting trust bug requires you to convince people to use your compiler binaries. The thing you're talking about just requires a patch to pass code review.

It's more work - you have to figure out a sneaky bug and write a legit looking patch - but anyone can do it. You don't have to be in a position of power already (e.g. being the Debian GCC packager) so overall it is much easier.