Let me try: selling it does nothing to promote its development and deployment. In fact just the opposite, especially when sold to a 'litigation specialist'.
It promotes development to the extent that the people being prosecuted
a) really infringe on the patent, and
b) would not have known to use the insights of the patent but for it having been published
This is because such people break the "good" kind of monopolies we want from the patent system. To the extent that the above isn't true, it reduces to the issue of "crappy patents being granted", not a problem with litigation specialists per se.
