There’s a discussion to be had perhaps but I guess one issue would then be the pitches and the rest of the ground infrastructure being used all year round and not getting the usual summer maintenance/returfing etc (plus pitches being too hard/dry if not watered).
Apart from the costs involved which can’t be supported in the Women’s game yet, also need to consider what happens if, say, Durham, Lewes, London City etc get promoted from the Championship ? They’re not affiliated to ‘big’ league clubs.