evidence. Just opinion.
I see a difference between:
I believe BYU made a mistake in not joining the Big 12
and
BYU made a mistake in not joining the Big 12 when invited.
There are some strong opinions on both sides and if I were to make a choice I would probably line up on the side of BYU missed a chance because of what BYU did rather than what the Big 12 did. However, I don't know.