Yes, he does actually talk sh*t on his own players in press conferences regardless of how the team is performing, I forgot about that. I guess that's a trait he has all the time, not just when he is losing.
I think you're scraping the bottom of the barrel to try and fashion his treatment of Shaw and Martial into a success story. To me they came good despite the treatment, not because of it. All I see is wasted time in their career development where Mourinho wasn't improving them, and publicly smashing them. They also had their own adversity to deal in this period with which would've given them more life experience and mental strength than anything Mourinho said.
Now they are starting to look like what they looked like before Mourinho got hold of them, in my opinion. I don't think Mourinho bashing them publicly had anything to do with their upward trajectory.