We've had two No Kings marches and millions showed up

[haele]

21. Difficult to do. Land doesn't vote.

And there's a lot of empty land out there between the majority of the population.
One or two million in three large cities does not affect as many legislators as needed.
And too many Congress folks and policy wonks (and the Media) see all that "land" in a district as being a larger population compared to a city that might have two to four Congressional representatives.
Hell, there are States with a smaller population than a city like Houston or Oakland.
Heck, Wyoming and Alaska have less population than most any one of the bedroom community cities surrounding San Diego...and another three or four states have a smaller population base than the city itself.