I don't think we will ever see relegation come to college sports, but there needs to be a hard reset from the current format. Just like when Div 1A and1AA were separated, it's ridiculous to think that Alabama and Alabama Birmingham are competing for the same thing.
One program is willing to spend whatever it takes to compete for the national title every season, the other is just praying that they get enough payday road games on their schedule in order to support their athletic department. It's a completely broken system and it no longer makes sense to continue it.
Separate into two divisions. The first will be 60-80 schools that meet certain requirements such as attendance, stadium size, willingness to pay cost of attendance, size of AD, whatever makes sense and have those schools compete primarily against each other and in their own Divisional National Championship. The remaining schools, primarily all G5 do the same. Who cares if The B1G/SEC allow a G5 Representative into a 12 Team Playoff annually. They are not winning it, next year or 100 years from now.
Why not have a tournament where you end up with a competitive final four of teams like Boise St, Coastal Carolina, Army, and SDSU? It's good for TV as you have more product to sell, and it's good for the teams because they are actually competing for something real and will receive the lion's share of the proceeds from the second tournament.