While I think the Constitutional blueprint for America calls for a two-party system (at least) to remain viable as a democracy, we all know that time changes things. Nothing lasts forever. The Republican Party certainly seems to be of fresh ideas. Revitalization of the Party will require thoughtful consideration and planning. A Constitutional Convention would provide the right context and the right working forum.
Frankly, I think the Republican Party has become corrupt since Donald Trump assumed the role of the Chief Executive. I don't feel that he was an effective president, and I suspect there are many of us Americans who would agree he was dishonest, and has shown that he is not mentally well-balanced. (Aside from that, his niece, Mary Trump, spoke openly about his behaviors and his psychological traits. (As she is a trained psychologist, I think she spoke with authority and appropriate conviction.)
His dishonesty and his narcissism were blatantly on display, and he was not amenable to coaching or psychological adjustment. I believe his motives were suspect.
I suppose we all needed the experience of having a personality-disordered, fascist narcissist in the White House, so we could learn the traits of a potential Fascist Dictator, and thus what NOT to vote into the office of the presidency. We can learn some useful lessons from this last experience. I think there are many Americans who don't want to see another such example chosen and elected in the next 50 years.
For America to evade devolving into an authoritarian replica of the USSR or China, we DO need to revamp, or replace, the Republican Party. All things grown old and fail eventually. The "Grand Old Party" has run its course, and we're running out of time...our Democracy is imperiled. America needs a replacement for our Conservative branch.