For a business, somebody is getting paid to maintain self hosted servers on hardware (virtualized, on prem or in cloud) that are also not free, and besides the hardware cost you also have the cost of simply keeping them running.

For personal use, it is only free in the sense that you don't value your free time. Initial setup is the smallest part of it. If you intend on exposing your services to the internet, you also need to be on top of patching, reviewing logs and much more.

I've been self-hosting for decades, but these days i simply use whatever cloud offering fits my needs. It's usually cheaper, and/or much more resilient than what i had at home.