Not so sure it is Trump who is to blame for changes within the ranks of the GOP.
I am more inclined to believe the changes had occurred, and Trump either by chance or on purpose took advantage of the changes.
The changes included dissatisfaction with the GOP establishment along with a desire for nationalism rather than globalism. Also a more direct ardent confrontation with liberalism as in single payer, DACA, and so-called woman's rights, to name a few issues.
So I see Trump as more of an opportunist than someone who set out to alter the GOP establishment.
The one thing which is pure Trump is his leadership style which differs from previous presidents of either party in my view. Some welcome this, while others of us just, shall I say, cannot adjust.