I doubt that the TV money will suddenly dry up and it would affect all clubs hugely, only a handful could pay their wage bills without it, and they'd still be in a fair bit of trouble. Losing TV money through relegation would be the biggest danger, revenue would fall from £120m to somewhere around £50m in the first year and would further drop as the parachute payments fall. Everton would need to drastically sell off quite a few players and reshape the squad very quickly to compete in the Championship and then it might take a while to rebuild a competitive PL squad upon promotion.
Relegation needs to be avoided at all costs