I 100% agree with this. I see Apple sheeps against it and I’m not surprised at all. Lets see some reasons why they should let you downgrade your device:

• Because its your phone and you should be able to install whatever version you want in it. This is possible on macOS, Windows, Android, Linux… iOS is literally the only operative system that doesn’t let you downgrade
• Some people say that it would be a nightmare to support old versions: well, you dont need to. Does Apple support Yosemite? Tiger? No, they dont. They just move on and if you want to use those versions feel free to do it but dont expect support of any kind. I’ll add even more: App Store reviews should be disabled for devices running older versions to prevent people bothering developers. Easy solution
• Since around iOS 9, Apple has a tendency to release unpolished software. I can say that iOS 11, 16 and 9 were AWFUL. In fact, back in 2017 I had a brand new iPhone 7 that got ruined by the glorious iOS 11. It would have been SO easy to just downgrade back to iOS 10 and keep having a great phone… if your software is buggy, don’t force people to stay on that version
• Apple should stop treating their customers as stupid. If they want to downgrade, let them do it warning them of the risks involved.
• Newer updates make older phones slow. If I see that my phone gets slower, I shouldnt have to stick with it.
• I know Apple doesnt force me to update, but if something goes wrong or I simply want to do a clean restore with iTunes…guess what happens! Apple forces you to update to the latest version

I don’t think its that hard. macOS has been doing it since day 1 and the world is not burning. Windows and Android too. In fact, downgrading has been included in the right to repair demands. Some good examples: the iPhone 4 was borderline unusable with the iOS 7 update, the iPhone 4S was unusable on iOS 9, iOS 16 was VERY buggy during the first 4-5 months (there’s even a compilation of bugs on youtube).