Phil was the glue that basically Reigned in Tony and made sense of Mike and Tony's work and made it all work.
Without that, Tony and Mike left on their own were always in trouble and didn't even wait until they found a 3rd person or a drummer (having told Chester no thank you) to write with etc.
Huge mistake by rushing and maybe trying to prove a point. Sadly, they failed.
Even Ray said he wished he hadn't joined them at the expense of his own solo career.