The B12 commissioner is trying to zag when the other power conferences are zigging. He's expecting basketball to have growth and earn a closer share of revenue dollars to football over the years. So he's loading up on undervalued basketball-focused properties (Arizona, Houston, BYU, etc.) and worthwhile "leftovers".
His goal is P3. The top schools in all other conferences have joined the B1G or SEC, and FSU/Clemson have made it clear they're looking to bolt the ACC as soon as they find a way around the grant of rights or bully their way out. Yormark is seeing how tenuous the ACC's position is, and how many strong basketball-focused brands/schools the ACC has that won't be the top choice of B1G/SEC. The B12 was almost dead, and now he's trying to make the B12 a better landing spot for some of the basketball-focused ACC schools when the time comes instead of ACC teams staying and trying to poach FROM the B12. So he's getting UConn in right away to further enhance the B12's value in the run up to their next media negotiation and next round of realignment (easier to convince east coast teams from ACC that B12 will work for them if they have UConn as a test case and "friend" as it were... and keep us from the ACC as a decent fill-in when others leave).
From UConn's perspective, joining right away hopefully gets us more short term money while eventually getting us enough money when football joins and we get a full share to compete when the House settlement and revenue sharing of up to $25 million annually to players kicks in. B12 presidents don't want to give us football money that comes out of their share and ESPN won't give us full pro rata share because our football is garbage. So have to wait for a full re-negotiation in 2031, and B12 presidents are pretty skeptical about our football so they'll add some stipulations to protect themselves from us joining if we don't improve football so we're not a net drain on that future football negotiation. UConn would prefer football in right away, but it doesn't seem to be an option.