New iOS version adoption figures speak for themselves. Honestly it doesn’t sound like you are “most people”.

I mean, looking at https://www.statista.com/statistics/565270/apple-devices-ios... -- "earlier" versions stick around 5-10%, which was enough to keep people supporting IE for over a decade beyond its EOL. So, I don't think you have a valid argument.

5–10% of people using earlier versions absolutely backs up the statement “Most Apple users always run the latest iOS version.”

It’s not reasonable to compare native apps to browser support. Dropping support for an older version of iOS doesn’t cut users off, they can continue to use the more recent version of your app that supports their device.

It’s especially unreasonable to compare it to people supporting Internet Explorer for a decade. Microsoft halted all development for five years and people carried on using it much longer. Apple comes out with a new major version of iOS every year and nobody is using decade-old versions of iOS.

I’m currently on an iPhone 7 so I’m also stuck on an old version

It works fine so I don’t see a need to get a new phone, except less and less apps are going to continue to work eventually