I'm absolutely still using PCs from over a decade ago and I'm still getting security updates.
On Widows at least, drivers from the Windows Vista days still work just fine on Windows 11 as the ABI hasn't changed that much since then. Good luck with that on Android.
Should some government regulatory body like the EU intervene to force their hand? Maybe.
But do remember that in the "old-days" of dumbphones and featurephones you were getting no SW updates at all ever and replacing your phone every 2-3 years was the norm back then.
It's only now that we're thinking about this as we start to think about phones more as general purpose computers in our pocket and less as phone dialing and messaging devices, like in the old days.
One thing's for sure, it's that the free market will never self regulate itself on this matter, same how it has not self regulated itself in the auto industry were it not for the EPA and EU, we'd still be buying ICE cars that turn our cities into smog if we were to leve emissions to the auto manufacturers.
They are getting there and maybe someday they will be as they start to mature, but today it's just not realistic.