Actually, if I recall correctly, the question of whether an idea (patent) is "in need and marketable" is a criterion used by the PTO is assessing whether a patent may be granted (in fact, I believe those are the exact words they use). I don't recall whether this is in regard to a new patent, or a recert, but there is a "requirement" that the patent owner do something, themselves, with the idea (we had some discussions here in the past in this regard - one of the values of having TPL as a partner - they directly use the tech). So if marketability is looked at, a view of licensees to date may support our cause. And that marketability reveals the "need".

FWIW, (sorry no link)

SGE