The “conservative” part of right-wing republiQan ideology was largely a lie from the start. The true goals of preserving power in the hands of rich white men were neatly folded into every “deregulation”, “fiscally conservative”, “tough-on-crime” and “trickle-down” talking point for forty years.
Trump’s success revealed the people who voted for those things don’t care a single bit about them because they could have enacted policies that would follow those supposed ideals, but instead they either did nothing or in some cases did the opposite.
“Barry Goldwater conservative” voices which had a claim to environmental protections were subsumed almost as a first act of the modern era starting with Nixon’s downfall.