It may not be of any use for government ministers to switch sides when the current government term is just about to lapse. It would do their reputation good if they remain on the gov't side to complete their term and face the next election.

If they genuinely dislike the leadership style of the PM, they should have switched side during the unsuccessful motion of no confidence moved by the opposition.

It seems that the Ministers and back benchers that have moved side have done so in an attempt to save face against the inevitable failures that would be leveled against the grand coalition where their term is lapsed.