About the security content of iOS 15.8.5 and iPadOS 15.8.5

Apple does support their phones for some time. But note that 10 years is only if you bought the iPhone 6s when it was new and at its most expensive. The iPhone 7 (Plus) wasn't discontinued until 2019 and is on the same iOS version. So it got something like 3 years of OS upgrades (impacting app support) and 6 years of security upgrades in the worst scenario.

Mate if you go by when manufactures stop selling devices, there’ll be android devices with _negative_ support years.

And that’s 6 years _so far_.

That's the fair way to look at it though. You don't expect to get three months' less warranty when you buy a model three months after release. It's also how the EU software upgrade requirements work: 5 years (or more) after they discontinue the model and stop producing it