Trump didn’t turn the Republican Party into the party of Trump. The GOP did it to itself. When the one time soul of the Republican Party, William F. Buckley, Jr., was alive he keep a tight rein on the party as to keeping out the riffraff of the far right and the overt xenophobes. But upon his death the powers to be not only let the bottom of the political barrel into the party, they aggressively encouraged them to join their ranks.
Now what little is left of the once true moderate and conservative Republicans have but three choices — blend into the Trump Party, join some other party or retire from politics altogether. And even if Trump (lock him up) is on the sad side of the bars from which to lead his collection of misinformed or just plain misfits, no problem, crook types are quite adept at leading their gangs from prison. Thus we can expect the party of screw everyone will continue to thrive as the opposition party to America’s better angels.