Apple has never sold updates for iPhones. What you’re misremembering is them selling updates for iPod touches back at iOS 2 because of some perceived accounting

Apple has never sold updates for iPhones. What you’re misremembering is them selling updates for iPod touches back at iOS 2 because of some perceived accounting issue, and the cost was pretty token, something like $5-10 IIRC correctly. Hardly a cash cow that would have had them making more optimisations then they do today