But the answer to your question is probably found in the fact that Trump never ran for any other office, much less served. (I could argue he never served as president either, he only took and had others serve him, but that would be bringing “politics” into it.) He ran as an “Outsider,” who was unstained by the inevitable compromises of working with others, who was going to run the country like a business. He did. If you look at how he ran his business affairs, it’s pretty consistent with his presidency.
He’s got a lot of power still in the Republican Party, without having to spend any time working on legislation or living in DC.