True, but there are ways around that. Using rep points is one - only threads and posts of value, by posters of value would count towards a potential forum's "score." Of course, there are other benefits to rep points, as well, but they, too, are a perhaps-flawed system that can be abused (as seen on FW).

Another idea is to open a poll in the closest existing forum or fora, asking for user opinions. Everyone gets a single vote, so there's no issue with "vote padding" except for getting friends to vote. To prevent junk registrations, require a "minimum FT age" (e.g. 90 days & 90 posts) in order to be eligible to vote. The vote may not be binding, but would give the TB an idea of user opinions in a quantifiable (if not scientific) manner.

There will always be abuse of the system, and no system is perfect, but I think one of the above two (or some variation thereof) would help greatly.