Yes, sure. But the difficulty about monitoring is not the hosting per-se, but hosting in different datacenters throughout the world abd keeping all these services up.
My monitoring should not show "just down" if users from location A can't reach it but everyone else can.
Yes, or a new company could post on Reddit, "would anyone like this service?" and spin up a replacement. Probably not worth it in this instance, but I imagine a lot of people sleep better at night knowing that Postgres is available to self-host, or from a variety of cloud providers.