Might be because since 2019 and the withdrawal of the US military presence in NE Syria, the relative prosperity of Rojava has plummeted. This draws into question exactly how 'autonomous' said autonomous zone was.
It seems like you're conflating sovereignty with economic dependence, which are two distinct concepts—being entirely economic independent seems highly geographically dependent. Few regions in the world are lucky enough to even have this option. For instance, you can be economically dependent on neighbors but still locally determine who runs the local courts. So it's not great evidence of how their society is run, particularly when other states—say, Afghanistan, where the current government has clearly exercised local sovereignty—have similarly been affected by the withdrawal of US troops and the seizing of assets.
Yet with this they were able to beat ISIS when others had failed.