External consultants (McKinsey, I think?) estimated 3.5 million homes short, and Gavin Newsom campaigned on building that much.
He's going to fall far far short of this goal, because he ignored it for the first years of his governorship, and is only making small moves now, but people trying to accomplish this goal are glad that he's starting to make these small moves.
However, any change will take multiple years to start having effect, and at least 5-10 years to actually solve, so even if he does all the right stuff, Newsom won't be able to say he solved until he's out of office.