Unfortunately the article doesn't answer the important question of "where did they go?".
My son is in a private middle school. There's a good chance they wouldn't be in private middle school if the pandemic didn't happen. He was very frustrated being at home with Mom and Dad. After a year, he was getting very angry and depressed. I didn't expect to be paying for private school, but given his situation, here we are...
I strongly suspect many students have just completely fallen off the radar. Who knows what will happen to them.
I think there are enough private schools to handle much of this.
And homeschooling is not “fallen off the radar” either.
But I don’t doubt some have fallen off the radar.
If public school attendence goes down in such a system, the school districts (and therefore the schools) get less funding, but tax collection probably doesn't change. Instead there will be a surplus in the general fund. California has a lot of formulaic budget requirements, so if attendence dropped enough, it might derail the rest of the budget, but I'm not familiar with how close to the requirements the school budget tracks.
In terms of teachers, maybe not, but in terms of facilities, any school that was around in the 70s-80s should have plenty of classrooms and lockers. And I imagine that as public schools shrink, there will be teachers looking at those jobs.
https://www.populationpyramid.net/united-states-of-america/
The 5 to 9 population is more than 1M less than the 10 to 14 population, and the 0 to 4 is ~300k less than the 5 to 9.
Unless a lot more kids immigrate to the US, school enrollment will fall by 250k per year in a few years just due to fewer kids.
Anecdotally, I heard from some public school teachers that when they moved to online school during the pandemic, some students, who previously were failing, blossomed and excelled, but went back to failing when in-person school was brought back. It turns out that in-person school doesn’t work well for everyone.