Well, the Big 8, like all other conferences, was eventually going to have to expand or be left behind. And the merger with the four schools from the SWC made perfect sense.
The HUGE mistake that the old Big 8 members made was to line up behind the leadership of Texas out of hatred for, and envy of, Nebraska's dynasty. Had they resisted Texas, the conference would have had a much better chance of survival.
Maybe Texas A&M would have still bolted. Ditto CU and Misery. Maybe even NU. But those defections became almost certainties as soon as Texas was anointed the de facto leader of the conference.