As far as I can tell Apple has the longest support lifetime of 6 years, followed closely by Samsung with 4 years of major Android OS upgrades and 5 years of security updates. edit: It seems that Googles new flagship phones now come with 7 years of updates.

Fairphone has 10years of updates and probably more in the future as it can be ublocked and flashed.

Apple should provide paid support for security and open/allow to unlock old phones allowing user to do the maintnance for themself.

And if they dont they should be forced pay for every single of those old phones that they force people to trash due to their decisions. Companies should be reponsible for their trash due to plan obsolescence.