Financial risk just too high. The big Six clubs want to eliminate the relegation risk, and have guaranteed income streams, like we see in American sports. The EPL agreed to relegation in exchange for major financial autonomy when they started in 1992. Yes, it is a huge tradition beloved by fans in English football, but it does prevent the big name clubs from breaking away, joining with other high revenue European clubs and maximizing revenue. To me, the closest comparison in college sports is March Madness-It prevents the highest football revenue schools from gathering together and maximizing their own revenue. Too much fan blowback at this point, so they haven't had the cajones to take the leap. YET. The Athletic had a recent article on the impact on Tottenham if they relegate. From below, their TV revenue share would drop from almost GBP100 million per year (I assumed the value divided by 5 years, then divided by 20 teams to keep the math simple )to less than GBP10 million. The jersey sponsor, AIA, would also likely decrease it's deal by 90%, due to lower visibility in a lower league. Wealthy competitors would scavenge the Hotspur roster. Applying this to college sports, Think Wisconsin or Nebraska getting relegated from the BIg 10 to The American, or worse the MAC, and you see why relegation will be a nonstarter in any future college realignment.