One should keep track of feral hives continously before drawing any conclusions about their logevity. Bee colonies come and go I have observed. It stands to reason that feral colonies would be affected by the same problems as kept bees, namely Verroa, IMO.
MB has been keeping track for a pretty long time Jack.
By breeding the queens he's collected, his strain has been
surviving (and thriving) without the use of pesticides for
a number of years.
There has always been a long standing debate as to the "age"
of any given swarm. i.e. a one or two year old package that
casts a swarm, these are not survivors. True survivors are
colonies that thrive without the help of man beyond five years IMO