>Just that for a specific belief to survive, some number of members need to survive to pass it on to the next generation, which if their beliefs bar them from killing or violence requires them to rely on people who aren't.

Literally every Quaker could die today and their beliefs would still survive because we can do things like write books and publish websites now. The spread of knowledge and culture isn't limited to direct person-to-person transmission, and it doesn't depend on anyone doing violence on anyone else's behalf.

How often do you see people trying to recreate the lifestyles or belief systems of extinct cultures / societies for themselves to live by in a genuine day to day manner, and not in a academic or archeological capacity?

The content of their belief system might be known and recorded in that scenario but the teaching of it as a genuine belief/truth to live by and to be passed on from generation to generation probably wouldn't be.