Git is also FOSS and is not owned by Microsoft / Github. Using git doesn't really "give" Github anything other than a bit of convenience and brand linkage. If the industry wanted to adopt a git replacement I suppose that Github's use of git could be a hinderance, but honestly the coupling is pretty loose.
Also, I worked in consulting for a few years and while Github was common, so was Azure devops (ironically also Microsoft, though) and one project used BitKeeper. Github might be dominant, but is very far from a "monopoly" in my opinion (I don't know if anyone used that word but if that's not the concern then what's the big deal?)
Yes, my experience is that Github isn't actually universal. I've yet to work for a company that uses it, personally. My only interaction with Github is in the hobbyist realm when I want code from an OSS project that is hosted there.
This has been my experience too. I think of Github as more like a social media platform that incorporates git as a convenient feature. Large corps use it as a marketing/PR forum and regular people use it to connect to other people interested in programming.
But what software are large corps use then? I work at a fairly large coorp (>650000 employees) and they are indeed using Github Enterprise (and some other solutions like Bitbucket data center). I'm would be quite surprised if they really only use software like Github for public things.
Azure DevOps is in a weird zombie state where everyone knows Github is getting all the development attention (and presumably most of the workforce now) but Microsoft is keeping it on just enough life support to keep companies "happy enough" and are still refusing to call it "dead". (They continue to point to the development roadmap, which is still actively maintained, but to some like me read very much like "bare minimum maintenance feature set". It also doesn't help that of the few open repositories for checking in on AzDO development, such as their community proposals repo, which are themselves hosted on Github, hah, it is very transparent most haven't seen active commits since 2019 or 2020.)
Bitbucket has a lot of Jira-integration and a lot of large corps are in Jira for the long haul now and "might as well get the synergy of Bitbucket".
Plus, don't underestimate the sunk cost fallacy factor keeping a lot of large corporations locked into things like Perforce and ClearCase.
With my last four employers, two used subversion, one used git (just git -- not github or the like) and my current one uses whatever Azure Devops is using.
I made a filter list for uBlock Origin (and compatible) ad-blockers that can hide many of the social media aspects of Microsoft GitHub to make it a bit more tolerable when forced to interact with it due to project lock-in.
I have seen it used on a commercial project, but I couldn't fathom why they were doing it. I guess business people did their thing. Large healthcare related project in the US.
An anecdote, but it's really difficult to search for information on git. Pretty much everything I find is specific to GitHub. Though that might be a problem with me still using Google to try to find information.
Yeah I switched to DuckDuckGo a long time ago and now I might switch to Brave Search because its "Goggles" feature is pretty cool (basically lets you rerank search results according to preference, ex: give precedence to tech blogs, or URLs popular in HN comments, down-rank most popular sites etc.).
This is getting off-topic, but at a certain point Google's results started to feel less and less relevant. Strict keyword matching stopped becoming a feature since it started to "guess" the "hidden meaning" behind your searches, modifiers like "include this exact text" and -"exclude this" stopped being supported and the amount of crap it throws in the search results that are not links to websites became distracting and annoying much of the time rather than useful.
I would suggest bookmarking this: https://git-scm.com/book/en/v2 I have found the how and why of pretty much everything I've ever needed to do with git there. You can also access the official man pages on that site.
TBF the argument that some people use GitHub because it offers a more pleasant experience than using git itself (via the CLI) might have some truth to it. But saying "GitHub is what most people use because it makes the complexities of git easier" goes a bit too far. Local git GUIs like Sublime Merge are better for that - GitHub might help you with the complexities of collaborating with others using git, but it won't save your ass if you've got your local repo in some wonky state...
Also, I worked in consulting for a few years and while Github was common, so was Azure devops (ironically also Microsoft, though) and one project used BitKeeper. Github might be dominant, but is very far from a "monopoly" in my opinion (I don't know if anyone used that word but if that's not the concern then what's the big deal?)