[danielmarkbruce]

They also said there isn't a physical reason, that is often meant to mean "it isn't a law of physics".

The fact that something happens doesn't mean it's a law of anything. Cars didn't exist before we built them - no law of "no cars". People died of TB before we had a cure - no law of "TB". Same for various types of cancer.

In practice when someone says "live forever", they don't mean to imply they'll live the 10^100 (or whatever the guestimates are) years to the end of the universe. They mean they'll stop aging in the sense that we do now. Maybe we could live to 10,000 or 50,000 or whatever. You can always get hit by a bus, or get some strange disease from a bat, or whatever.