Obligatory “Not a historian” but a software engineer, so I can’t provide formal scholarly articles. However, since nobody answered the question, I thought I’d chime in! ( Mods feel free to remove if it is not up to the subs standard )

I’ll be relying almost entirely on “UNIX – A History and a Memoir” By Brian Kernighan which provides a first-hand account on the history of the development of the aforementioned operating system and dedicates a chapter to discuss management practices within bell labs.

“Bell Labs” is a rather loaded name for an organization that has shifted and evolved trough time. For the purposes of this answer (and hopefully what OP meant) we’ll discuss Bell Telephone Laboratories as the specialized research and development branch that AT&T stablished in 1925.

It’s important to recognize that although indeed a for-profit company, AT&T was essentially a regulated monopoly. Rates were set and managed by the newly created FCC, this effectively guaranteed a steady and predictable income, with the objective of “improving communication services”. Mr Kerninghan quotes that AT&T spent about 2.8% of its revenue in R&D endeavors.

In the foreword of “A History of science and engineering in the Bell System” N. N. Hannay states that “Research is concerned with invention and discovery, and with the creation of new knowledge. These leads to technological development over the long term, perhaps ten, twenty, even more years” This sentiment of non-urgency, of detachment of immediate applicability to generate profit is shared by Mr. Kernighan and even praised as a principal reason of the productivity of Bell Labs. Since researchers needed not concern themselves with creating a marketable product, they could choose an area that was enjoyable or of particular interest and spend as much time as necessary to investigate curious phenomena.

At first, research was manly focused on physical sciences. Multiple Nobel prices (nine, to be exact) were awarded to scientists for work done at the labs: The transistor (1956) of particular importance to computer science, as the labs grew, so the scope and long-term objectives of their research departments so that in early 1960 a specialized computer research group was formed.

As an example of the freedom that researchers enjoyed at Bell Labs, Mr. Kernighan recalls that no one told him what he should work on, he wasn’t assigned a particular project, or directed to a specific area of improvement of an AT&T product, rather he was “encouraged to wander around, and left to find their own research topic and collaborators”, he even goes so far as to state that this management style wasn’t unusual: “This lack of explicit management direction was standard practice. Projects in 1127 were not assigned by management, but grew from the bottom up, coalescing a group of people who were interested in a topic”.

Management within research groups was often done begrudgingly, by scientists who would rather be pursuing their own curiosity instead of superficially following up on somebody else’s work.

Freedom was not completely unlimited however, Researchers had to submit a yearly report stating the value of the work they had produced which was discussed by department heads and was the primary tool to allocate yearly salary increases and possible promotions. In the case of lab 1127, these “merit reviews” where written by engineers for engineers, so even esoteric research on fields with low practical applicability were recognized as valuable. In any case, they didn’t need to justify a concrete application, merely that the work was valuable.

This almost unconstrained freedom resulted in a body of work that would have been difficult to achieve if short-term profit was important: UNIX was a pet project of Ken Thomson, work on directed graphs, and graph partitioning (like the travelling salesman problem) was at first considered esoteric mathematics before computational power improved to the point that it could be applied to very real problems that improved AT&Ts network.

Eventually, AT&T was broken up and bell labs was re-incorporated creating Lucent Technologies, which then merged with Alcatel which was recently purchased by Nokia. Valuable research is still being done, Alfred Aho and Jeffrey Ullman were granted a Turing award for work done on compilers.

I’m not qualified to say if the USA benefited from Bell being a monopoly, or if the research that was done there could also have been achieved under a fair market, but several scientists seem to share the sentiment that: since income was all but guaranteed; higher level management did not meddle and researchers where granted total independence what resulted was some of the most valuable pieces of technology that we enjoy today.

Sources:

Kernighan, B. (2020) UNIX A History and a Memoir.

Millman, S. (1983) A History of Engineering and science in the Bell System.