The vote was a bit closer than you might think for Prop 15, which was the last attempt, I think, to repeal Prop 13 for investment property. And in 2020 when that ballot measure was voted on the pro-repeal folks were nowhere near as organized as they are today. As I said in another comment I think there's a good chance that if they take another run at it they will succeed in repealing it for investment property because they will message aggressively that they're not after homeowners, which is what the investors convinced the electorate the last time they tried to repeal it for investment property.

And on the topic of residential, up until a few years ago if you died your heirs were allowed to inherit your tax basis, no strings attached, and so the "staggering" you're talking about has never really "staggered" en masse (if I'm understanding the way you're using that word). On top of that, even people who purchased property as late as 2020 are already massively benefiting from Prop 13. Each day home prices appreciate the new homeowner population just keeps replacing the dead in the anti-repeal camp for residential.

Edit: I was trying to put a footnote but it turned into italics so I just dropped the footnote