Very well said. And the idea that the GOP is somehow a private entity that has no obligation to the bigger issue of free elections in this country is absurd. A similar argument would be to say that our local electric companies have the right to turn off power to a city or state as a bargaining tactic to raise their rates.
Our political parties have evolved over the last 200 years as a means to facilitate the narrowing of candidates to a manageable number for free elections to work effectively. For free elections to work, that narrowing process itself needs the input of the people.
While never a perfect system, the people created the parties years ago, long before this current crop of insiders were ever born, and have the rightful expectation that they will serve the purpose of facilitating free elections. They have become part of the process to such a degree that if one of the parties rigs the result this late in election season, the system makes it next to impossible, with many state ballot deadlines already having passed, to mount an independent run for the Presidency outside one of the political parties.
Ah, but not really.
If Trump decides to run a Third Party, rules created by Republicans to keep him off the ballot would be deemed unConstitutional, would go to the Supreme Court, and he would win.