Being able to lock in a low interest rate for thirty years, the probable lifetime of the amortization period, is very advantageous. Combine this with a lack of a prepayment penalty and American mortgage holders get a great deal.

That's somewhat understandable given that the alternative is pretty much writing a monthly rent check. In that respect, it's a bit different to my mind than an auto loan. (Maybe if you compare it to a lease.)

If you didn't have 30 year fixed mortgages in the US, property values might indeed drop somewhat. But it would mostly advantage people who had access to other capital. People who can't afford houses in expensive areas now mostly still wouldn't be able to.