Why not just insist new clubs need to buy into the league initially?
Full funding is based x-number of positions in the league and reduced/zero funding for clubs wishing to join initially or that finish in a certain position.
After x-years, number of funded positions is changed depending on upcoming TV deals and either it covers everyone or if certain clubs can't afford to continue without funding due to their standing in the league, they naturally will have to drop out?
Promotion based on initial investment, and relegation based on lack of contribution. Encourages clubs to put their money where their mouth is whilst at same time challenges current clubs to prove their worth or pay for it.