You are assuming more time and more people will make jb happen faster. That's like saying if we double the number of cooks in the kitchen dinner will be ready in half the time.Let's say they have jobs, and work the same amount people normally do. That's roughly 40 hours a week each, that in theory, could be added to the JB process. Compound that over a few people and over a couple of weeks and the time is substantial, not only for finding new exploits, but for squashing bugs incredibly quickly.
Even the most superficial browsing of MR, the Dev-Team blog and any discussion forum that deals with jb shows a large majority of threads filled with people complaining about how long the development of the current jb is taking. This happens with every jb but has escalated recently. It is unfortunate MR moderators and administrators refuse to deal with it. Since this increases the number of visits, members and posts, I suppose the increased ad revenue explains this neglect.
This whining from a small band of self absorbed malcontents with a sense of entitlement is without having paid anything for a jb. If they had paid money for it, the level of complaining would skyrocket which might allow MR to charge advertisers even more, but would surely drive away the more valuable members of MR, leaving MR an electronic wasteland.