A&M - they were tired of being in TX shadow and everyone knows the SEC is tops for football. Perfect fit for TAMU and perfect response.
However, TAMU had also been in a major rut and needed a shot in the arm as well. Perfect timing with their Coach and Johnny Football as well. The TAMU of just the years prior would have gotten creamed.
Missouri - the SEC is tops.
Nebraska - tired of TX calling the shots and their ego was too big too share.
Colorado - pathetic program needing a change and made a move to hopefully gain some help. Joke of a program for several years now.