I wish more people would have seen through this, but alas.. this is the real reason. Corporate pressure, agenda, not the best interest of the open source community.
"1) Some contributors are actively blocked from contributing code to LLVM."
> These contributors have been holding back patches for quite some time that they’d like to upstream. Corporate contributors (in particular) often have patents on many different things, and while it is reasonable for them to grant access to patents related to LLVM, the wording in the Developer Policy can be interpreted to imply that unrelated parts of their IP could accidentally be granted to LLVM (through “scope creep”).
[..]
> This is a complicated topic that deals with legal issues and our primary goal is to unblock contributions from specific corporate contributors."
Legally dubious relicensing was not only unnecessary, it is now preventing 9.0> use and future contributions, OpenBSD, which has a long history of opposing Apache 2.0. And using LLVM/Clang as the default compiler for the kernel/userland and a ports tree with 10,000 software packages.
How is a reverse patent retaliation clause in the Apache v2.0 license not in the best interest of the LLVM community? It provides more patent protection for LLVM
At this point, OpenBSD has decided that two very popular open source licenses (GPLv3 and Apache 2) are unacceptable to them. That has walled them off from a lot of open source software. They seem to think that it's incumbent on everyone else to adopt licenses they like. They are going to continue to be disappointed.
Addressing the patents question seems to be the main reason.