Apple has much better support for their phones, you can get iOS 17 on Xr which was released in 2018. On the other hand pixel 3 which was also released in 2018 lost official support with android 12 but of course in android you could just flash a custom rom and call it a day. So I don’t think it’s fair to say you need to upgrade every “couple” of years given the average user probably upgrades every 3-4 years regardless if they use iOS or Android.