But you realise that adds things like an extra row of icons, video previews, redesigned Siri interface, redesign the control centre etc?
Plus, you’ll need to see if iOS updates are actually the same across all devices or generations. iPhone is different with every phone - so quite possible.
iOS updates aren’t going to magically add AV1 support , 8K or any hardware that comes out in those 10 years. Hell, took them close to 5 years to support YouTube 4K and they can’t even support some of the latest Netflix features.
So yea - it can quite easily make a difference as when to buy the correct hardware in the hope that something in those support years is actually functional