In reading The Idea Factory[1] it became incredibly clear that Bell Labs only released and licensed a great deal of this technology as the results of various antitrust settlements that plagued the company throughout its entire existence. Also, part of the role of the labs appears to have been to give the company something to "show off" whenever congress or the DOJ complained about the extraction of monopoly rents. I highly recommend the book, it was really fascinating to see the degree to which many of our assumptions about the functioning of the labs and its relationship with the corporation are in fact historically inaccurate.
[1] http://www.amazon.com/The-Idea-Factory-American-Innovation/d...