Until you have an idea of where to put that additional 200% of our current population, yes, SF is full.
At the margin, there's a lot that could be done - density bonuses, putting teeth into the Housing Accountability Act (SB 167), approving 4400 units in the Baylands, upzoning along transit corridors, approving ADU's (granny units).
Developers have lots of ideas about where to put people but are generally blocked by NIMBY's at every turn.
You can call your supervisor about all of this.
The hard part is not where to put all these people, but to invest in the infrastructure to serve them.