I quote from the NCAA memo:
If an institution is selected to host a preliminary round(s), but that given institution’s team
is not selected to the championship, the institution will still be required to host. … 16 predetermined regional sites will be selected; and of those sites, eight super regional
sites will be selected at the conclusion of the regionals
So it’s possible that if somebody completely crashed and burned in May, they could host but not be in the tournament at all; however, they will select sites on merit. But the 8 super sites will come from the 16 regional sites.
It’s not that much different than now. If we were the 4 seed and TCU hosted and was paired with us, and we lost in the regional, the super would be in Fort Worth.