If the state delegates are required to vote for Trump at the convention, and Trump is to have the number of delegates that for now we know are required for winning the nomination, then please explain why this matters.
It doesn’t matter. The pool of people willing to drop $5,000 to $10,000 to be meaningless extras in a TV show is limited, and a state party certainly has a right to look to its own past time and financial contributors to represent them. Fringe party participants that usually expect others to pay their way are naturally not high on the list.