Problem with that is time is ticking - clubs have to know what division they're in so they can build a squad appropriately, price tickets at the right level, etc. We're only just over a month away from when the Scottish season kicks off.
It's an unholy fudged mess - either punish Rangers properly and forego the money they generate, or say "This is an unprecedented situation, for the sheer financial well-being of the game it is better in the long run that Rangers stay in the SPL". This is the best of no worlds if it happens.