Regardless of whether a company has an admin with necessary qualifications or not, their time is not free and can be used elsewhere.
In the company where I work we do not have anything but network equipment in the server room (500 employees distributed across Europe). All „self-hosted“ solutions are on AWS instances behind VPN, and there are only four 3rd party systems of this kind, where investment in self-hosted setup did make sense at some point (two of them will be replaced with commercial SaaS soon). We of course have a devops team capable of maintaining those systems, but this is not given that it worth it.
When talking about „self-hosted“ solutions it is important to consider all factors that contribute to TCO. It is not as simple as getting some hardware and running an installer.