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.
