Most of the Big Ten's moves have been in reaction to the SEC. This is no accident, the Big Ten had to do something to keep up with the SEC's increased value after each expansion. The Big Ten understands Notre Dame is the only midwest brand that would help them do that but Notre Dame has had no desire to join the Big Ten. The Big Ten did not want to live in a world where the SEC made significantly more money than them. Outside of creating a national conference, how exactly would the Big Ten keep up?
In retrospect, the Big Ten committed to becoming a national conference when they added Maryland and Rutgers. They obviously didn't add those teams for the football brands or because they were a good geographic fit. It was about creating a national footprint. Having Penn State, Maryland and Rutgers gave the Big Ten access to the huge Eastern markets. The NE corridor (DC-Baltimore-Philly-NJ/NYC) is still an extremely important region to control. After UT/OU went to the SEC, the Big Ten knew it needed to add value. They decided to acquire the 2nd largest media market in the US and a blue blood program. Then they've waited for the PAC to die without their top market and will likely go back for OR/WA to control the entire west coast. Maybe not, maybe LA is enough for them. I think we'll find that out soon.
But the prize has always been the south east markets. That's where people are moving, economies are growing, where the best recruiting is, and where the most passion for college football is found. However, ESPN now controls the SEC/ACC. That's effectively shut the Big Ten out of the most prized region. But there's a lot of unhappy campers in the ACC right now. I'm interesting to see how this part of the story plays out because it's more interesting.
TLDR version: Of course Penn State, Michigan and Ohio State "could cut it" without USC and UCLA. That's not what this is about. It's about how to keep up with the SEC long term.