Unfortunate reality of CA is that or every resident that's moving out there are two people going to take their place.
Actually, for every 6 moving out, 5 are going to take their place, per the article. But I suspect that a lot of the out migration isn't from the urban economic powerhouses and most of the in migration goes to them, so that for urban California, your statement may be closer to true, though exaggerated.
Yes, the article specifically about internal migration doesn't address external migration.
> California nets about 100K or more immigrants from outside the US each year, which would cover the gap in recent year.
Sure, but it doesn't change it from near balance to anything but even nearer balance; it's nothing like 2 in for 1 out on a statewide basis.
California's population has grown every year since at least 1960, but the headline and article would make you think otherwise.