And all of it is somebody's "theory" in the end anyway.'
That only things after 2233 would have changed is what Spock comes up with, in-universe. But does that include Kirk looking different from Prime, or is that part just movie magic?
That things before and after 2233 would change because time travel connects everything is a theory deriving from how Star Trek works. But time travel works differently with different time machines. Again, we can't even tell whether Kirk's eye color "really" changed, let alone whether Spock going to see his 7-yr-old self would be endangered by Nero, or be relevant in any way.
That nothing would have changed but the historical events is a theory that is not at major odds with anything seen, because we have to squint anyway whenever we watch Trek, any Trek. It's possibly supported by Spock Prime recognizing Kirk 2.0, and not contradicted by anything much, but in the end it's as theoretical as these musings get.
All of the above works. None of it needs to.
Timo Saloniemi