Wow, that just gave me a PTSD shudder. I started at one shop and they had a small team continually fighting against their home rolled message queue and task runner. After joining in the fray, asking about a million questions about why this is done like that, etc., I talked them into replacing it with a stock Python Celery setup. The original author of the local version protested, understandably, explaining why it couldn't possibly work.
It worked. It didn't require handholding. It continued working after I left there.
My coworker was a smart guy, but he got it in his head that their specific use case was something that couldn't possibly be served by a COTS project. Turns out, it could, and easily.
This story is more common than any of us would like to admit, myself included.
I can say this with some confidence because as a junior developer, I was often that person, and I didn’t really understand the collective lessons contained within e.g., Rails, Celery, etc.
I was enamored with doing something “cool” and “interesting” and I didn’t realize that this was distinct from and not actually as cool as solving someone else’s problem on time and under budget.