There was a time when Dems dominated everything.
US House - 40 years: 54-94
US Senate- 34 years: 54-80, 86-94
They had the majority of governorships.
They also had a majority of state legislatures.
That isn't the case now.
They have a 3 seat majority in the House, only tied in the Senate, but due to having the White House having Senate control. The GOP still has control of more governships and control a majority of the state legislatures.
The Dems needs to break that GOP grip. Structurally, even though they are more Dems; the structure favors the gop on the presidential level thru the electoral college and the senate level. We are seeing the damage done at the state level, with so much gop control.