Okay it's not the only reason, but certainly one of primary ones. All proprietary software developers had issue with GCC long before switch to GPLv3. GNU declin

Okay it's not the only reason, but certainly one of primary ones. All proprietary software developers had issue with GCC long before switch to GPLv3. GNU declined all attempts to make compiler IR accessible for 3rd-party software which would make proprietary extensions possible. And yeah it's the reason why LLVM take that niche. Also GPLv3 was officially announced in 2005. It's was just matter of time before all GNU projects switch to new license version. And it was certainly. https://www.zdnet.com/article/gpl-3-may-tackle-web-loophole/ https://www.zdnet.com/article/gpl-3-may-tackle-web-loophole/ Oh and there was plans to release GPLv3 even earlier in 2004 and it's was known that it's will include patents grant. This was obviously absolutely unacceptable for Apple: https://www.zdnet.com/article/look-for-a-new-gpl-in-2005/ https://www.zdnet.com/article/look-for-a-new-gpl-in-2005/