You cut to the chase on a lot of issues, and I agree with a lot of your points. In other words, you present a concise blow-by-blow of how the right has routed the left starting in the 60’s, omitting various skirmishes and shiny objects that less-incisive analysts give undue attention. To play back your core points, the left ran out of steam in the 60s, the right went to work, the left appeased them, and government became dysfunctional.
Another 60’s element might be that the working class perceived the hippies as taking over the progressive movement previously led by culturally mainstream people like FDR. At which point, the working class turned away from progressivism because they didn’t like its perceived counter-cultural affectations. Hence Reagan's "Morning in America."
The right capitalized on this as seen in the Tea Party trope “Keep your government hands off my Medicare,” in effect “I like progressivism, but I don’t like progressives.” We see today that Overton-window-friendly progressive causes have clear margins of majority (but the right has shackled progress on these causes).
That said, and with the betrayal of progressivism by Clinton et al aside, I’m uncomfortable with blaming the left for not playing hardball, for three reasons:
(1) The right has more successful messaging because it is based on fear. We see in today’s media (social and broadcast) how fear-based messages over-power all others.
(2) The media environment is more prone to propaganda, which the right doesn’t hesitate to flood people with.
(3) As you say, the right is happy to lie and cheat. The truly structural solution is to make sure lying (like crime) doesn’t pay. If the GOP were a pro football team, they would foul so aggressively that they would “win” in spite of the penalties. The rules have to be rewritten so that penalties include losing the game and getting kicked out of the league. Impossible as that might sound, any other solution is too superficial to succeed. If recent legal actions (14th amendment!) and judicial decisions against the right continue to mount, they might get to a tipping point.
