So what? Will that negate anything positive he does?
No. It'll just prevent him from accomplishing much that is positive, and make it more likely he'll screw up and accomplish things that are negative.
Ever work for or be commanded by someone who believes they're always 100% right about everything? Who never listens to advice from people with more knowledge or experience, and who gets angry if any subordinate suggests that what they are saying or doing is a bad idea?
The most important thing beaten into our heads as Marine second lieutenants was to listen to our staff NCO's. To do more listening than talking so that we wouldn't sound like jackasses. Some followed that better than others. The ones who didn't were the ones who made the most mistakes, and who lost the respect of their troops.
That's how I see Trump, except he started off with all the power of a general but none of the experience. The guy so certain of his own genius that he refuses to take any advice even from the people he appointed. The more experienced, competent, and respected the appointee, the more likely Trump will refuse to listen, and will get pissed when told something he doesn't want to hear.
Most lieutenants who make that same mistake learn, and are better captains than they were lieutenants. Trump has actually gotten worse.