Author here. The "monolith" I'm describing is an application-level characteristic. The deployment container, whether it's a bare metal server, a VM, or a Docker container doesn't matter.

I admit that my definition is not necessarily universal, but IMO the characteristics I listed are all highly desirable. I pushed for this model when I worked at Amazon (an AWS service as 1 monolith) and I've seen it work great even at large scale (close to 10K hosts, millions of requests per second, etc).