Tucker Carlson is a liar, ignorant, or both. Let's take Tucker Carlson at his word that he hasn't kept any promises, and that is the only conclusion.
Heck, he could just go over to a campaign promise tracker by one of his liberal brethren to find a few more: Washington Post Trump Campaign Tracker Website
Trump has kept most to all of his promises that are within his control. Tuckers point is that he doesnt know how to deal effectively with the swamp politicians to get the big permanent things he wants that they are reluctant to give him. For example he doesnt know how to twist their arms like Johnson, Obama or some others did to get their way. Sending tweets and making public statements certainly havent moved the politicians much. They only gave in on the tax uts because their business donors BENEFITTED, much more than individuals.
Carlson isnt a liar. He certainly is not considered ignorant by anyone. He may say things you dont like or agree with. So do we all.
As for gop turnout, the conservatives rightly didnt want to reward a do nothing, not trump supporting congress led by dirtbags like Paul Ryan. They were not going to reward those clowns for their foot dragging. At the same time the anti trump forces were at an all time high energy caused by constant anti trump publicity.