On a very practical level the right has been prioritizing the winning of local and state elections for a long time, while the left has been dreaming of the Progressive Revolution and the President who will Get Us There.
So, yes. State legislatures matter—a LOT. Governors matter. Even county government matters. And the left needs to stop looking for a Savior and start filing the paperwork to run for statehouse seats, etc.
(Am I, personally, running for my state legislature? No, my life circumstances don’t allow for that. But I am certainly willing to put forth the effort to remind people of how important it is, instead of losing myself in fantasies of the Patriarch who will Save Us–as alluded to earlier, there’s too much of that in the Bernie “movement”. It’s not necessarily the case that Biden will be the center of any such cult, but even so—we need to think locally.)