but can't we separate what was good and what was bad so that the good things happen without the bad?
No, we can't. That is impossible.
Because the "good" and the "bad" are different views of the same facts.
What was "good" for middle class white men was, frequently enough, bad for poor people, minorities, and women.
What was "good" for the USA was "bad" for European countries - much of US prosperity in the '50s was due to Europen factories being demolished during WWII, so to 'get back' to those great days for white, middle class, American men would require a destructive world war in which US infrastructure was relativy unscathed.
Such a war is no longer possible.
In WWI, British infrastructure was barely scratched, because the technology of the time meant that it was impossible for her enemies to strike effectively over the distances involved.
In WWII, technology had advanced, and planes could carry large bomb loads from Germany to England, and vice-versa. It was no longer possible for the UK to prevent large scale damage to infrastructure. But transatlantic flight was not yet practical for bombers; The USA was left with her infrastructure intact.
Today, the world has intercontnental missiles, long range aircraft, and submarine launched weapons that can destroy entire cities. When WWIII happens, nobody will be left with intact infrastructure and the ability to get rich selling stuff to the folks whose stuff was destroyed.
It would be lovely if things were as simple as you fondly imagine them to be. But they aren't. Reality is complex, and your desire to return to the past founders on the twin rocks of "things have moved on" and "it wasn't really as good as you remember".
We have to handle things as they are right now; Turning back the clock is impossible. And, of course, that was true back then, too.