A few things:
1. With the SEC expanding to 9 games, I do not see a school like Kentucky wanting to give up a home game that is an automatic win. 9 SEC games and 2 OOC games is what it would be with every other year being 6 home games.
2. Outside of Georgia and Florida, P5 teams that play neutral sight games don't do it every year. If you look at schools like Bama, Ohio State and LSU. They play 7 home games every single year, with maybe a random exception once in a blue moon. They schedule to where if they have a neutral site game, they still make sure they have 7 home games.
3. Some schools, like Michigan are very strategic around home games. They play 7 home games a year. If one of those home games is lost for a neutral site game, they make sure they play 8 home games the prior year so they can average 7.
3. Kentucky alternates between 8 home games and 7 home games, depending on where the UL game is. If they played a neutral site game (which I would also love), I can almost guarantee that they would 100% do it in a year that they have UL at home, to still guarantee 7 home games.
Unless the new expanded playoff format can guarantee that schools could recoup a majority, if not all, of the revenue from losing 1 home game a year every season, I don't see it happening. That's way too much money to give up imo.