Bernie was already a useful case study. When you control like 1% of the vote in 1 house of Congress the best you can do is add amendments that minimize damage. Or go with purely partisan stuff that doesn't needlessly damage your chances of getting committee chairs, which are arguably important as they're another axis on which electoral power from a small minority could be exercised. Idk why anyone expected them to be able to pass anything of significance. Don't get me wrong, small left wing fringes are important to legitimate harm minimization, but at the end of the day they are never going to turn back neoliberalism without either a ton more Congresspeople supporting them, or massive protest or strike movements behind them.