IMHO, the reason Trump shot to such sudden popularity in the Republican primaries in 2016 was because he embodied something they’d been wanting: Someone who would attack the entrenched GOP establishment, finally deliver the goods the base had been wanting (a border wall, deportation of illegal immigrants, etc.) and also argue that white people, men, etc. are victims too. In a game of horseshoes, Trump was the horseshoe thrown the closest to this imaginary candidate that the GOP base had been wanting.
But Trump also came with a great deal of baggage: his Access Hollywood tape, his divorces, his 100 Tweets per day, his immaturity, behavior being more akin to a 7-year old than a 70-year old, etc., ignorance of global affairs and many things, etc.
When Trump leaves - be it by impeachment, death, resignation or voluntarily after 4 or 8 years in office - Republicans aren’t likely to go back to normal candidates. They’re going to try to find someone who is like Trump, but doesn’t have his baggage. Indeed, they will want someone who is even more Trump than Trump. Someone who will show even more focus and discipline in getting that wall built, people deported, etc. Someone even more ruthless, but with none of his flaws. I would guess someone like Tom Cotton (R-Ark.), perhaps. Or someone else.
This means that current Democratic proposals to prevent a future Trump very likely won’t work. Demanding that all future prez candidates release their tax returns, for instance, may pose no problems at all to a future Trump 2.0, who might be a candidate with a perfectly clean financial background and nothing to hide. Someone with no divorces, no rap sheet, no Russian/foreign interference, who is highly intelligent, cunning and savvy and ***really ***knows how to be a dictator.
Republicans have a history of trashing their ex-presidents or ex-candidates (there are many Trumpers who now condemn George W. Bush, John McCain or Mitt Romney) and there is no reason to think Trump can’t be thrown on the landfill as soon as they’re done with him - that is, if they can find an even more Trumplike person than Trump. This new future Trump 2.0 could convincingly argue, “Trump promised you a wall, deportations, this and that but didn’t deliver, but I’ll really deliver.”
TL;DR; Republicans have been wanting an even savvier, more Machiavellian Trump.