Not Bell Labs specifically, but its parent company AT&T had a vertically integrated monopoly which gave them control over essentially all communications technology, and also virtually all telephone service, which it used to dictate (high) prices and constrain the growth of their competitors.
Now, the monopoly profits AT&T may have been worth it, because without them, AT&T would not have funded Bell Labs creating among other things C, Unix, the transistor, the laser, and photovoltaic solar cells.
I will just note that if you want to measure it was worth it, consider what the GNU in GNU Linux is commonly held to stand for.
Not just current, more like "in general since the 70s". This was mostly due to the legal doctrines of Robert Bork, who was Solicitor-General during Nixon and held great influence from the late 70s, which stated that the only good reason to engage in antitrust was to increase consumer welfare (and implicitly, if antitrust would reduce consumer outcomes, antitrust is wrong). The idea basically boils down to "the customer is always right."
Now of course, many arguments being made today are that where the negative effects of a monopoly are felt aren't primarily with consumers, but with smaller enterprises being squeezed out, and with workers at a monopoly deprived of choice, both commonly cited with Amazon. Bork's stance was that these aren't legitimate reasons to engage in antitrust and really end up protecting inefficient existing enterprises.
Anyhow, Bork's Antitrust Paradox (https://www.amazon.com/dp/0029044561/ref=cm_sw_r_cp_apa_fab_...) was and is one of the most cited books in antitrust law, mostly to make the case as to why antitrust in a particular situation is not merited, and the Supreme and lower courts have adopted views from there directly dozens of times.
So it's not just a recent thing, it's a long running, over 40 years now thing
Now, the monopoly profits AT&T may have been worth it, because without them, AT&T would not have funded Bell Labs creating among other things C, Unix, the transistor, the laser, and photovoltaic solar cells.
I will just note that if you want to measure it was worth it, consider what the GNU in GNU Linux is commonly held to stand for.