Last year was the best year for the PAC12 in the last several years.
I don't know how the teams from the PAC12 compare to the teams in the BIG12 this year, but losing Texas and Oklahoma definitely makes winning the BIG12 championship this year a bit less difficult.
Consider - in 2019, Utah was 8-1 in the conference and was in the PAC12 championship game.
In 2019, Texas was 5-4, going 1-3 against ranked opponents, and was only bowl eligible due to OOC wins over the likes of Rice and LA Tech. They were in a 4-way tie for 3rd in the conference, but tie-breakers gave them official 3rd place in conference - they just as easily could've been 6th.
And when they met at the end of the year, that Texas team curb-stomped Utah. The game wasn't close - Utah was never in it.