Funny. Except there are fully supported MacBooks from 2013 running the latest version of macOS, still on their first battery, still bringing people joy and productivity.

Or in my case, a 2012 MacBook Air. I hope they'll support Catalina for another three or four years or at which point it's more than a decade old and can finally mature into a laptop's final stage of life as a Linux machine.

They tend to support OS releases for three years. Catalina EOL is likely to be sometime in 2022.

I stand corrected. I'd attribute my false confidence to the fact that even the previous version (macOS 10.4 Mojave) is still supported. But now that I think about it that'll likely change at the Apple WWDC in June.

Still, decently satisfied with ~10 years of software support for a laptop.

Mojave Support ends this year right on time for 3 years. I finally left Mojave behind myself as I really wasn't using the older apps catalina lost support for anyway.

Late-2013 MBPs still came with replaceable storage unlike the M1 Macs, no?

Yup. My personal machine is a base Late 2013 15” MacBook Pro (8GB RAM). Original battery, original storage, it saw very heavy usage up until a a couple of years ago. Still fast, decent battery.