Also hypervisors get escape vulnerabilities every now and then. I would say that in a realistic scale of difficulty of escape, a good container (doesn't matter if using Docker or something else) is a good security boundary.
If this is not the case, I wonder what your scale extremes are.
A good container has very little attack surface, since it can have almost no code or tools available, a read-only fs, no user privileges or capabilities whatsoever and possibly even a syscall filter. Sure, the kernel is the same but then the only alternative is to split that per application VMs-like) and you move the problem to hypervisors.
In the context of this asked question, I think the gains from reducing the attack surface are completely outweighed from the loss in functionality and waste of resources.
Yeah, what I mean is that it's useless using ports like 2222, that's like the unofficial SSH port! Bots are generally harmless (once you move to key auth), and you get functional the same result with the automatic IP ban on failed auth, minus the bother to change client configurations to your custom port. Anyway, if someone does want cleaner logs, changing port works :)