Yep. This is game theory. He has calculated that he has no chance of winning the election using the conventional strategy of appealing to the middle (based on scandal after scandal). So, his only hope is to (a) drive up turnout among the people that will vote for him no matter what, and (b) depress turnout by saying as many nasty things about Hillary as possible and hope that some of them stick. He accomplishes that by going back to Primary Donald, which successfully employed that strategy.
It's still a very long shot -- and he likely knows that. But it's better than what he is doing now, so he's gonna give it a shot. The next 3 weeks are going to be a very tiresome time. I can already see it in my social media feeds. After days of near silence from Trump supporters I'm starting to see things creep back into my feed. He's going all in, folks.
Giving Trump WAY, WAY too much credit here.
This is just a man who doesn't know how to win, but super doesn't know how to lose (funny as he's been doing it his whole life and never learned how to not make it worse for himself)
More than likely he never really intended to get this far, it worked better than he could have imagined, thought for a moment "hey maybe this is real" then stepped in his shit a million times and realized "oh yeah I'm Donald Trump... schwang wang wang"
And now his deepest insecurities are coming to light as even his feeble lackeys in the GOP admit, yeah you are fucked and we can't have this.
So now he is just lashing out, not in any kind of strategy, just cause he is a bitch and thats all he knows how to do. Shit on everyone so he can crawl back in his hole and tell himself that once again everything isn't his fault.
Now perhaps people around Trump have cooked up insane strategies like this, clearly Bannon and Ailes and whoever are stroking his hate boner. But lets not pretend Trump himself has any idea what he is doing.