From HawkCentral.com, July 8, 2022:

Iowa athletic director Gary Barta said Friday that it took less than a week's time for the Big Ten to welcome USC and UCLA into the conference. The California schools made contact, the university presidents and athletic directors quickly mobilized and soon they had two new member schools.

Barta admitted that the SEC adding Oklahoma and Texas last season pushed the Big Ten into conversations about expansion. They didn't want to expand just to do it. They carefully thought about what characteristics they wanted to align with: a strong academic and athletic footprint, reputation and the sort of financial impact they move would bring. In USC and UCLA, they found additions who bring big-time brands and, likely, big-time TV cash. 

This obliterates my personal contention that this deal was weeks and even months in the making. It seems clear both schools wanted out of the PAC-12 badly, while the B1G saw adding them as a manna from heaven to countering the SEC adding Texas and Oklahoma, and they moved quickly and quietly to get a deal done.

While Barta’s remarks validate the B1G prioritizing schools that excel both academically and athletically, they also underscore their need to be able to carry their weight in gold in terms of athletic revenue and ROI—brand power and TV revenue. The B1G isn’t taking ”brands” that aren’t going to put more money in its members’ pockets. That’s not basketball or baseball or tennis. It’s football.

Is the B1G done? I personally don’t think so but I also have nothing to base that on other than I can’t see the B1G leaving USC and UCLA geographically stranded 1,500 miles from the nearest B1G school (and 200 miles farther than Rutgers to Nebraska), no matter how much more money they will make in the B1G. But as fast as they moved, how much was bringing in other PAC-12 schools discussed, if at all? If it wasn’t, it shows how much they realized their athletic survival pivoted on negotiating to get out of the PAC-12 as quickly as possible.

There are no unconnected events: a butterfly flapping its wings in California can cause a tornado in the Southeast. If, when and how everyone else reacts to the B1G’s move remains to be seen.