Yes, there is money to be made... most free tubes get stale after a while, if people are into a specific niche or a model. Also they canīt provide the GF (girlfriend experience) that cam sites do
Only thing going for the tubes right now is the dvd content guys are not policing the tubes, and the dvd content resellers either donīt have the funds or the exclusive rights to do it on their behalf.
Many paysite companies/guys/gals with their own exclusive content are very good at keeping their content of the tubes or at least make it hard for it to stay long. You donīt hear alot of them desperately complain (sales are down for most, but at least they donīt loose sales to tubes that pirate their content, and get indexed by the SEs).