They did, Cinci went all in trying to get in relaignment and played all home games at Paul Brown this year due to the expansion.
They'd really be better off just making Paul Brown their home permanent home venue. It would be a lousy college stadium, of course, but it would a lot easier and cheaper than trying to make Nippert a legit stadium.
The Bungals probably wouldn't be thrilled about it, but they don't own the stadium, so they probably couldn't stop it.
Ohio is actually the one state that probably doesn't have enough p5 teams (I guess Louisiana as well).
Ohio has the perfect number of P5 teams.
That said, no one is legitimately afraid of Cincy rivaling Ohio State, even if they get back in a power conference. The Kelly years were a sham and no sane recruit is ever going to pick Cincinnati over Ohio State.
"Major" is stretching it when it comes to Cincy and Memphis.
Won't speak for Memphis, but it's not a stretch to call Cincy a major city. The city proper is shrinking, like many other Rust Belt cities, but the metro area is 2 million+.