is to create a large enough gaps between the "haves" and the "have nots." Once that gap is there, then it can be easy for the power conferences to show that the "UNLVs of the world" don't have the sustainable resources to live in the "semi-pro" world full time. At that point the power conferences announce they will be forming a new division level under the NCAA umbrella or a new association all together. If it is under the NCAA umbrella, then the division levels will probably look like this:

DI - power conference schools
DII - the old DI-G5 schools
DIII - the old DII schools
DIV - the old DIII schools

If the power conference schools decide that all schools will participate in all sports, then that should kill any attempts for politicians to force the conferences to add undesirable schools. Now if they decide to allow schools to continue deciding which sports they want to sponsor, then there will probably be pressure to add partial members for sports that are consider to be "non-revenue" (i.e. ice hockey, baseball, softball, track, golf, water polo).

Now if the 4 super conferences decide to break up once in the new division level, then I could see them adding a few members either to meet a minimum requirement or to get back to some desired number. I don't think you will see all these conferences try to go back to 12 members because either the bylaws don't include a CCG in football or there is a new postseason in place that make the need to hold a CCG obsolete/less valuable.