In one respect they'll live forever as the vb runtime will continue working on the microsoft OSes that exist today. VB6 apps still work in Vista, for example. VB6 applications will be impossible to support going forward when microsoft stops supporting the VB6 runtime on its operating systems.
This means that they will probably continue to live forever, much as some COBOL applications still live today. New code should almost never be written in the effectively dead language, now, though, so the marketability of VB6 skills will be in a progressive decline until some low, steady-state remains.
