Although there are people who cares about updates (like me), I want to say that majority of people probably don't care or even aware about updates. There’s a reason why the Chinese have no problem selling cheap phones that are getting practically no updates at all.
The regular people treat phones in a different way than techies/enthusiasts. Most people see phones just like an appliance. Some use it as a status symbol, ie. they don't care what OS in it as long as it's the most expensive model of that brand.
I, too, care about updates, but I'm also not one to keep a phone more than a few years. I replaced my Pixel 2 XL in November, primarily because it was losing update support, but I was also about ready for something new (though that phone is still a great device!). I replaced that with a budget-friendly 4a 5G, but that will also get 3 years of updates/patching.
My dad, on the other hand, isn't one to do the same, and he's still using a 3 or 4 year old iPhone. Oddly enough, my mom is on Android and is still using her Pixel 3, but there has been discussion about moving her to an iPhone. She's following the same upgrade plan I have - replace when it loses patch support (so she'll probably be upgrading in November).
The issue really comes in to play for the people that are more budget-conscious. They either are behind on updates/patches from the get-go because they bought the cheapest device they could find, or they buy a slightly better one but keep it so long they lose their patch/update support long before they're ready to let it go.