You know, you gain seats by gaining population. Just because one state is growing faster doesn't mean another is losing people. Those are hardly dependent nor even expected (California gained it's massive population despite an overall high growth rate of the rest of the nation).

"Losing people" (total population dropping) isn't quite the same thing as "exodus" (large number of people leaving) though.

We know for a fact that people are no longer moving to California in large numbers from other states. That's more than a little bit suggestive of the overall context, of what's happening. And it's a big change from what used to be normal for California in the past, as it used to pull large numbers of people to it from other states.

It's very obvious what's going on with California, why people no longer flock to it, and it's going to get a lot worse yet rather than better. If the flight from California isn't obvious enough yet, it will be. Given California's population growth has already stagnated, what comes next is going to be decline.

declines take 100s of years. No one will really notice but it will just slowly continue to get worse but not at any kind of satisfying pace, like a big crash.

California grew 6% from 2010 to 2020 while the country grew 7%. Hardly a smoking gun.