Never underestimate how much of the current crisis is caused by people who think or thought they were doing good. Prejudiced idiots with good intentions is the chorus in the song of history and something we must always be cautious not to fall into ourselves.
A lot of the people responsible for driving the "suburban experiment" in the 50s/60s would've self-identified as science-minded progressive urbanists in their day. They weren't, but they probably genuinely thought they were. It was easy enough to not realize how awful their "science" was, how brutally regressive the policies were (especially for how they affected poor and vulnerable populations). They didn't understand the environmental catastrophe it represented or the financial timebomb it set ticking. They thought they were building better cities for a brighter tomorrow that would benefit everyone.
Just because the effect was "I got mine, fuck you" does not mean that was the goal. A lot of these people didn't even consider the downsides of these policies because there were vanishingly few major voices challenging them. Yeah, there was also a lot of capital interest involved and undeniably a lot of legitimate conspiracy (especially re: trolleycar destruction), along with a VERY stateist postwar news media that give us a bit of a chicken and egg problem, but the reality is that the zeitgeist was pretty seriously bought in.
That's a big reason organizations like Strong Towns push so hard to try and upend the current development pattern -- return cities to slower, organic, community-driven growth instead of large top-down projects. It's because we often have terrible missteps when we jump in and start wildly building all the new hotnesses.