I understand the point you're trying to make and I agree that FreeBSD tends to have cleaner code and better documentation at different levels but I don't think that it makes it that much more difficult. If you dropped in from a different world and had zero experience then I think you're right and a systems team would almost always pick BSD. Any actual experience pretty quickly swings it the other way though; there are also companies dedicated to helping you fill in those gaps on the Linux side.
I've built a couple embedded projects on Linux, when you're deep on a hard problem, the mailing lists and various people are nice, but the "source of truth" is your logic analyzer and you debug the damn thing. Or your hardware vendor might have some clues as they know more of the bugs in their hardware.
Fair points taken, i was a bit zealous in my use of the word any, the word many is more correctly applicable.
In regard to sources of truth, i mean from the design considerations point of view. For instance, why does the scheduler behave a certain way? We can analyze the logic and determine the truth of the codes behavior but determining the reason for the selection of that design for implementation is far more difficult.
These days yes, off the shelf linux will do just fine at massively scaling an application. When netflix started building blockbuster was still a huge scary thing to be feared and respected. Linux was still a hobby project if you didn't fork out 70% of a commercial unix contract over to rhel.
The team came in with the expectation and understanding they would be making massive changes for their application that may never be merged upstream. The chances of getting a merge in are higher if the upstream is a smaller centralized team. You can also just ask the person who was in charge of the, let's say for example, the init system design and implementation. Or oh, that scheduler! Why does it deprioritize x and y over z, is there more to why this was chosen than what is on the mailing list?
The pros go on and on and the cons are difficult to imagine, unless you make a vacuum and compare 2024 linux to 2004 linux.
I've built a couple embedded projects on Linux, when you're deep on a hard problem, the mailing lists and various people are nice, but the "source of truth" is your logic analyzer and you debug the damn thing. Or your hardware vendor might have some clues as they know more of the bugs in their hardware.