The concessions obtained through SocDem goverments in European countries came about because all those countries had thousands of actual communists in varying posts in the government and the concessions were to reduce class consciousness and weaken the communists.
To understand the magnitude of difference, imagine if the US House of Reps (total seats 435) had 40 honest-to-god Communists in power, with another 80 left-of-Bernie SocDems : thats what the French legislature was like in the 60s and 70s.
Instead the US has 3 extremely mild SocDems who may or may not be grifters.
I hope you see the magnitude of difference here, there is no real way of moving the admin left and whatever minor leftward shift you may see is what the ruling class themselves, by their own accord, decide is necessary to keep the threat of civil unrest from getting too high.
So whenever you see any liberals IRL or online talk about how we need to become like Norway or whatever, remind them No Communists in govt = No European style Social Democracy
There is absolutely no pushing Biden left. I don't even know where people come up with that or the 'harm reduction' talk.
Look at the DNC convention and all the Republicans they gave more speaking time to than the progressive SocDems.
The message is clear - fuck you if you're poor. This is the "middle class president". Again, fuck you if you're poor. Biden is going to be George W Bush 2.0 and that's what they want. This presidency is going to be a NIGHTMARE of them waging naked class war on us. They aren't even waiting for the election to talk about passing austerity budgets. He has NO plan whatsoever for the insane unemployment rate and worst economical conditions since the great depression. NO plan at all except to push austerity and make the working class foot the bill for capitalism in decay.
The first thing his admin is going to do is start pouring their efforts to outing progressive SocDems in offices, even if that means funding Republicans in races. They don't care. Just nominating Biden is enough of a metaphorical middle finger at you and a reminder of how much the Democratic party absolutely hates you. The psychopaths who run the Lincoln Project have been waiting for Trump to be gone so they can put to use all that money donated to them by jackass liberals, and start funding and building up Republicans to run in midterm races and that's exactly what's going to happen.
Biden will have a year to get the economy and unemployment straightened out, which he has no plans for since he wants to push austerity. When he fails and also the compounding factors of the pandemic, it's going to create a massive backlash from the right wing and our next reactionary movement is going to be make the Tea Party and Trump look tame in comparison.