Even then, I would expect most orgs would want to contract out to a company that manages an instance of that open source software. That management company could undercut bigger players because they don't need as many engineers working on features. I don't see where the LLM comes in and shifts the calculus here.
Or you can just ask your LLM to install https://github.com/CollaboraOnline/online
Between open source, LLMs, and SaaS vendors getting greedy and privacy invasive, the total pain minimization calc might shift for some orgs.