"Masses of Minneapolis Police from all precincts, including SWAT and a State Patrol surveillance helicopter, swarmed a protest for the police killing of Tyre Nichols as it was about to start in SE Minneapolis in single digit temps. No officers were seen getting out of their vehicles & no arrests. Crowd dispersed."
Among all the failures yes unquestionably WW1, FDR's exit, COINTELPRO , the red scare, US army domestic psy ops and the wave of assassinations in the 60's had a huge impact . But that's a given, we know the bourgeoisie, the war lords and so on will do everything to subvert and kill the left .
So yes today , "they" [ the security state, the bourgeoisie the right] may not be able to completely kill multiple largely impotent disorganized movements, but what they can do is effectively the same or perhaps even worse . The state can marginalize them to irrelevance, coopt them, infiltrate them, create chaos and so on more effective then it even did through the "counter culture" era. Its simply a road to nowhere in the end but as you said yes it's something to start from . Any display of outrage is frankly welcome at this point .