In my opinion, it can only be him. If it's anyone else, it will fall over and won't go anywhere. Trump is the only person with the credibility, trustworthiness, integrity and name recognition to be able to start a new Party and have millions sign up to it.
Also, of Trump starts the new Party, unlike him being President, this will create a legacy that will last for centuries to come.
The Supreme Court justices he picked will in a few decades be replaced, but a Party that genuinely represents the people, the affects will be seen for decades and centuries to come.
Does anyone else believe that it can only be Trump, and that if anyone else starts the new Party it will just fail?
Look at the Tea Party a few years ago, i believe it didnt get much traction is because it had no real leader, it never became an actual political Party.
Probably all parties were started with good intentions. Whatever party we start will eventually get corrupt.
I think that Trump must start a party as the GOP won't give him or any member of his family another nomination.
However the best long term solution would be for all states to secede and provide a free market of states for people to move to. A competition among states and not bail out will provide people with options where they can live with those that have similar political beliefs.