Having good home attendance in football is nice, but that doesn't make money for anyone else. For another conference to want to bring you in, you have to bring something to the party to share. Kentucky basketball would be attractive to any and every other league -- name recognition, TV ratings, NCAA tournament payouts, packed houses when the Wildcats come to town. Kentucky football? Doesn't move the needle at all.
In that respect, UK and KU are more alike than different, although Kentucky's football program has been better supported over the years than Kansas' has been.
Luckily for the Cats, it's just a hypothetical because their league isn't cracking apart!