As I’ve noted many times, Donald Trump was elected over the objections of the GOP establishment, and owed nothing to them. As a result, he was in a position to govern as a man above party, and to sell himself to the highest bidder. He chose not to do that, but the GOP Congress has been unable to accomplish anything meaningful to date, so why not dismiss them as a pack of pathetic losers and make deals with Democrats? He even gets good press and better poll ratings that way.
The problem is that Trump has identified himself so clearly with the policy priorities of the GOP that to change course now, particularly on tax cuts, would look ridiculous. In addition, his only real political skill is throwing red meat to his base. How is he going to make deals with Schumer and Pelosi while concurrently sucking up to white supremacists? I don’t see how the blue base would permit it.
The more likely outcome is that Trump will position himself as a Don Quixote figure, bravely (if with mixed success) battling the swamp creatures–Republican and Democrat alike–in Congress. That will play well with the base, but it doesn’t bode well for the GOP in 2018.