If a proposal is viable, the original author doesn't really play much of a role in its continued success. Minimum number of people for a successful proposal. "Viable" means the original author DIDN'T disregard the requirement to have a community ready to build it, or fake their way through that process.
Unfortunately, I don't actually see any viable proposals in Area 51 at this time. I've become pretty good at calling these things early on through years of hard-earned experience watching 10,000+ proposals come and go, but folks don't like it when I close things on that assertion — they have to discover it for themselves— so I just have to wait for things to timeout.
There's really no way to "transfer content/support across" if you simply restart the proposal again. When someone squanders the time and effort of others on ill-fated activities, folks have a tendency to just move on. You would likely have to find a community in sufficient numbers with a renewed energy and drive to actually build a Q&A site.
If you're passionate about a subject you see dying on the vine, use this time to rally a community to do it better next time. But a proposal resubmitted quickly after one has just failed comes with added scrutiny. I can’t let folks simply resubmit the same failed proposal over and over hoping someday it might just barely scrape through. That would not lead up to a healthy launch which is the whole point of this process.