Trump's an incumbent, the most successful one since 1984. Why have primaries?
It's up to the party as noted. But if you're going to claim "the RNC have more respect for the people" you can't run around cancelling the window of opportunity for those people to have a say when there are three nationally-prominent Republicans contending.
Can't have it both ways.
Last time we had an incumbent they still held the Democratic Party primary here. My choices were (1) Barack O'bama, or (2) "Uncommitted". Had there been, say, Hillary Clinton, Nancy Pelosi and Jerry Brown (former POTUS candy, prominent Rep and a governor, same as the present Republican roster), then it might have made more sense to vote in that primary. But they still held it even with no challengers.
They'll say it "saves them money". I'm not sure how it costs them money but hey, that's their problem. If they want to run a political party they're gonna need money. But you can't sit here and tell me "Republicans respect the will of the people" while they're cancelling primaries so they don't have to deal with challengers.
Having it both ways: nuh-uh.