"...the most pervasive and important technologies start in the public domain in government laboratories and universities, then move to instrument makers and capital goods manufacturers with strong R&D and only in the final stage to large consumer goods industries and services." (Freeman and Soete, 1997, 186)
In a couple of monographs on his website Baumol suggests that if firms were able to capture all the rents that spillover into the public domain, most folks would still be living with an 18th century standard of living.
Ian