No matter what, no matter how we disagree with their system, the system that’s in place belongs to the Republican Party. They get to decide their rules. As long as the rules don’t change midstream, what can we do about it? It’s been this way forever.
Just because Trump & sons convince the people to buck the system doesn’t guarantee that the Republican Party will change their way of doing things. They may cease to hold power, but they can do thing as they wish.
Maybe Trump will force change, but as it stands in this election, if the candidate decides to run under the Republican Party name, then they are assumed to be agreeing to, and accepting of, the party rules as they are.
So even if Trump wins, the only thing IMO that might cause the winds of change to blow out the Republican Party, would be for Trump to run for reelection as an Independent, where even the plurality winner takes the nomination — if that’s the way they want to set up their rules from the start.