My understanding is that both Bell Labs and PARC were owned and operated solely by large corporations (AT&T and Xerox, respectively). Do you have a source on government funding of either?
I don't know about the structure of PARC, but I suspect it's not quite as comparable to Bell Labs as you make it sound.
Weren't both of them funding some of their research projects via direct government (DARPA, etc) grants?
AT&T was a government monopoly. They had no meaningful competition that required rapidly innovating AT&T's core products, and they had lots of profit due to their monopoly status. They could afford to dump money into research (in addition to whatever gov't research grants they were getting) and still have plenty of profit left over. That's not quite government funding of research, but many economists will say that given its monopoly status, what it did was de facto government action.
PARC did some great things but they didn't have as broad a range of research as Bell Labs, did they? Xerox never had a monopoly like AT&T did, although I'm fairly sure they got plenty of government research grants.
There were also a lot of open fields in hardware and software that were just starting to be explored back then. Tech companies were investing plenty of brainpower and money into R&D, given little pushes by government grant availability. I think the difference in AT&T's case was the breadth of research due to how much profit they had... again, due to monopoly status.
PARC never had substantive DOD funding, it was funded by the largess of Xerox. Bell Labs did do government work, but was largely funded by the Bell Operating Companies, in the form of a royalty.
Exactly, the biggest research driver is military spending. Procurement is a huge way in which these companies were funded, eg the DOD bought 90% of computers in the 50's and 60's before they became viable as consumer devices in the late 70's.
PARC is heavily DARPA-funded today. In the 70s, PARC hoovered up a lot of Stanford grads who had been working on government funded projects at SRI. It's unlikely PARC would have been as successful without them.
Bell Labs was independent, but there are similar indirect links - lots of freshly minted PhDs cutting their teeth on government funded research, then moving into industry.
Government seed funding was directly responsible for the Whirlwind and TX series projects, for IBM's SAGE system, for the work of important consultancies like Bolt, Beranek, and Newman, and the various ACs (Illiac, Multivac, etc) all of which laid the foundations of modern computing.
IBM, DEC, and eventually Apple and MS productised that work, but it simply wouldn't have happened without government support.
Weren't both of them funding some of their research projects via direct government (DARPA, etc) grants?
AT&T was a government monopoly. They had no meaningful competition that required rapidly innovating AT&T's core products, and they had lots of profit due to their monopoly status. They could afford to dump money into research (in addition to whatever gov't research grants they were getting) and still have plenty of profit left over. That's not quite government funding of research, but many economists will say that given its monopoly status, what it did was de facto government action.
PARC did some great things but they didn't have as broad a range of research as Bell Labs, did they? Xerox never had a monopoly like AT&T did, although I'm fairly sure they got plenty of government research grants.
There were also a lot of open fields in hardware and software that were just starting to be explored back then. Tech companies were investing plenty of brainpower and money into R&D, given little pushes by government grant availability. I think the difference in AT&T's case was the breadth of research due to how much profit they had... again, due to monopoly status.