Publishing source code, if anyone uses it at all, is not "free" in any sense. I know several people that stopped open sourcing their projects (not even businesses) because the cost of making their code available isn't worth it.
Moving the goalposts to doing a great job internally also requires those things. Meanwhile, doing a perfectly fine job of FOSS requires none of them.
A great public codebase likely needs to be more understandable, more generic, more self guided, more error proof, more auditable, and more pluggable. Additionally, supporting popular open source at all comes with a deluge of requests, demands, audits, and obligations.
I expect these two converge as your "internal" consumer base grows big enough but for a small, cohesive team an internal-only codebase seems to me like a much much easier beast to tame.
Literally none of that is necessary to publish a source code tarball. You keep moving goalposts. You don't need heavy community involvement and support self-hosting and all that just to publish your source code.
I mean feature requests will come, sure, but people working with closed source software receive those too.
Yes, obviously, it is essentially no effort to just tar a folder and put it on the internet if you do literally nothing else and don't care at all what happens next.
Only solving your own problems on your own hardware while being able to rely on your own well-informed team to bridge the gaps sounds much much faster and easier to me.