For example...?
There are examples on almost a daily basis. There was a primary in New Your last week with multiple primaries on track for this week. Additional contest are scheduled into June. The Rules Committee met last week and affirmed the current rules without change. Daily, the candidates are being forced to defend their positions and to build the teams necessary to win in November.
By his own admission, Mr. Trump is new to the political arena but I think we could agree that he is better equipped to compete in a general election now than he was when he first announced. Cutting off the process now would deprive him of the opportunity to learn the skills necessary to win in November provided he can win the nomination. If he doesn't have the skills and strength to win at the convention, he would likely not be able to successfully compete with the democrat nominee in November. We need to find that out before he becomes the nominee, not after.
All endeavors have rules, both formal and informal, and if you choose to compete, whether it be in real estate, manufacturing, retail, sports, or politics, you must abide by the rules of that game. If you want to develop a real estate project, you certainly don't start erecting buildings before you have signed, sealed, and recorded title to the land you want to build on. Other developers may be out there trying to get the same property and they are justified in using all legal means to do so. Seeking the Republican nomination for president is no different.
Winning a majority delegate vote at the convention, whether on the first or later ballots is the final step equivalent to clearing title and recording the deed in a real estate transaction. That is the process and it is on track and will play out regardless of what you, I, or anyone else thinks about it.
As I said earlier, I want to win in November and I trust that you do also. I believe our best chance is with whichever candidate has the skills to win the nomination in the real world rough and tumble battle known a politics. This is not professional wrestling nor is it a ninth grade civics exercise. The democrat party, including their mainstream media wing, will go all out to destroy our candidate and he better be prepared because crying "foul" or "unfair" will fall on deaf ears.