Yours is a really accurate accounting of recent history. At least under Nixon, the EPA was formed. Republicans started attacking that institution during the Gingrich era.
In my opinion, here's the deal.
It's about power. For that whole century, Republicans were the party of oligarchy, but they had to behave very differently when the country's politics were against that. So if you look at the 1956 Republican platform, it sounds like Bernie Sanders. The country's culture at the time was still the FDR era. Republicans left in place those top 90% tax rates even though they held all branches. You had to look to find the oligarchy.
By Nixon's time, see all the things I cited how 'behind the scenes' he and the Republican Party launched the modern totall serving oligarchy agenda, but Nixon well recognized the political issues to 'look' more moderate. And he was right. His approach led him to be re-elected by 49 states.
We could list a lot of policies where he 'appealed to the country' by supporting more liberal policies, but let's let a secret recording of him talking about it show his views.
They are universally disdainful of arms control. While Nixon was beginning the bomb the hell out of Cambodia (one of his least popular policies), he remarked to Kissinger: “Looking back over the past year we have been
praised for all the wrong things: Okinawa, SALT, germs, Nixon Doctrine. Now [we are] finally doing the right thing.”...
As for arms control, Nixon told Kissinger that
“I don’t give a damn about SALT; I just couldn’t care less about it.” On the kinds of technical matters that concerned security wonks, like the number of radars or missile interceptors, Nixon privately explained that
“I don’t think it makes a hell of a lot of difference,” and that he thought the arms controllers were real
chumps about this kind of thing. He opposed an anti-ballistic missile site in the nation’s capital because:
I don’t want Washington. I don’t like the feel of Washington. I don’t like that goddamn command airplane or any of this. I don’t believe in all that crap. I think the idea of building a new system around Washington is stupid.
Which you have to admit is sort of a novel argument against anti-ballistic missiles, right? Because you don’t actually like the nation’s capital that you’re President of. He dismissed the Biological Weapons Convention as “
the silly biological warfare thing, which doesn’t mean anything,” as opposed to what he considered the really important stuff — again, the war in Vietnam.
He 'didn't give a crap' about those 'liberal policies', domestically or on things like arms control or banning germ warfare; it was political maneuvering. The people want an EPA, fine. People give him way too much credit as actually supporting those policies.
And that's the story with Reagan and Bush, they would do what was politically expedient, but push right. And the politics of the time make them look more moderate in hindsight.
At the time Reagan was rightly seen as too much a right-wing nutjob to be president by many, he'd led the right against Medicare; in hindsight people point at 'look at his compromise to save Social Security, look at his moderation on gun control, look at his amnesty for undocumented immigrants'. While he historically put the country on the road to oligarchy much more and had many terrible, radical, criminal policies.
You mention by Gingrich, Republicans were attacking the EPA; do you know who Reagan's Secretary of the Interior was? Or remember Ann Gorsuch, radical and corrupt anti-environmentalist who eventually resigned in a scandal, and was mother to the now terrible Supreme Court Justice Alito?
Traitor trump is a 'next step' in that process going beyond plutocracy, to not only naked plutocracy but authoritarianism, openly trying to steal the presidency (the party, not just him). Where hundreds of candidates ran on a platform of stealing elections. It's a progression I point to Nixon on and the systemic changes to have 'big money' take over politics.
The last time we had more democracy was the 1980 election, when both Reagan and Carter ran using public funds, and there were 1,000 or fewer Washington lobbyists, before exploding to 35,000, and members of Congress spending half their time dialing for dollars, with several billion dollars spent per election deciding who wins. Changes from the Nixon period.
And it's more complicated than that. Fox is a huge factor, with its own motivations about making money, for example, but it results in the current situation with oligarchy the dominant threat to the country.