I get where you are coming from but here is why I think things slow down:
1. There is a history of doing 2 and waiting a decade or more.
2. Both the B1G and the SEC have their hands full with what is going on now - absorbing 2 new teams each, transfer portal, NIL, litigation, new schedules, and the expanded CFP. The B1G has Ore and UW to deal with, or not. To suddenly start trying to expand just doesn't make sense from a perspective that there is already enough disruption.
3. The ACC has the GOR - neither conference wants to get involved with that - they will have to extract themselves first.
4. Both conferences are going to get blow back from the lesser teams who don't want to bring in better teams. At some point Ole Miss, Vandy, MSU, Arky, Ky level teams are going to say, enough. We can't win now and you want to bring in Clemson and FSU? Are you fucking crazy? You are already seeing the SEC having a hard time talking those teams into the 9 game conference schedule.
5. Then you get to the money, although that might should have been no. 1. If you want to deal with 1-4 above, there better be a ton more money. Other than ND, no other teams delivers that. Even Clemson and FSU aren't sure fire $100 million players. So, there better be a lot of money now, or it's not worth the effort - for now. You also have the biggest player on the media block, ESPN in some financial tightening mode.
In some ways, it's better for the SEC and the B1G that the ACC's hands are tied. I think they would much prefer to wait 10 years and see what the landscape is before expanding. If each school is bringing in 100+ million per year, is there really an advantage to getting bigger, especially for the mid and lower-tier teams.
For a long time you read all the time about super conferences, but not so much any more. I think a lot of people just got caught up in the hype and didn't think it through. Why not wait a decade or more to see how the litigation shakes out, see how the expanded CFP works. NIL has already changed massively in just 2 years ... those stupid upfront contracts are toast and teams are spending NIL to keep people on their roster and pick up transfers. Imagine what it will be like in a decade when we may have players unions and players getting paid directly.