(1) All batteries degrade. Really not sure why you think Apple would be any different.
(2) Replacing the battery is simple. You take it to a phone shop or to Apple and in about an hour it is done. Most people aren't self servicing electronics or pretty much anything these days.
(2) Replacing the battery is simple. You take it to a phone shop or to Apple and in about an hour it is done. Most people aren't self servicing electronics or pretty much anything these days.