No one said that the Vanguard continuity will be destroyed or made untouchable, there is the Manhattan story still going on, albeith very slowly, I have the Worldwalkers story that waits to be completed...
Just, if story teachs, the last time everyone wanted to continue to write about the TOMB/MBL serie side by side with the Hero Revolution one (Chewy had a cool solo series, Odissey, if I remember correctly), but in one or two month, the old Universe was all but forgotten.
In any case, anyone is welcome to continue to write the Vanguard Universe, IMO.
By the way, the Vanguard International story, the last one, was somehow slowly but not much more than the previous one, and IT HAS been completed.
If no one other has been started, I think it's not a problem of the collective writing, but of the general interest in the Vanguard continuity. The proof is that we were four at the start of this thread, when we talked about, basically, starting issue 20 of Vanguard, but when the possibility of a complete restart has surfaced, much more people are showing, with renovated interest.