How relevant to it is this though? Like never - not once - have I ever heard of someone upgrading their phone because their version of Android was too old.

It's far more likely they'll upgrade due to degraded performance and/or battery life packed into these updates with either new features (or more like, anti-features if we're being cynical). Want to use a smartphone for its lifespan? Don't upgrade software unless you absolutely need to. This actually applies to any computers really.

If anything, thanks to manufacturers like Samsung slowly overwriting android with their bloatware crap most people aren't even aware of what version of android they run because it doesn't even look anything like any other version of android on any other phone, unfortunately brands like Samsung succeeded in creating a soft walled garden for users by obscuring the fact they're using anything but 'A Samsung'.

Ask a non-tech savvy user for a USB-C charger, and they'll not know what you mean, but ask them for a Samsung charger and they'll hand you USB-C.