All the 2020 Democratic primaries did was settle who the nominee was for this year. They did not settle the question of what sort of Dem could be nominated for all of eternity.
And it's bogus to call Bernie "far left" or use that label on AOC or anyone in "The Squad". "Far Left" is the Khmer Rouge, not a revived New Deal, which is all AOC and the rest of those you called "far left" are backing.
I'm supporting Biden to stop Trump...the vast majority of progressives are...but you're not going to get those who aren't to do so by making spiteful dismissive posts claiming that it's futile to ever nominate a clear progressive. Treating progressive activists as if their entire project has failed for all time is a purely destructive and useless strategy.