It maybe a rather odd interpretation but I tend to think of this as being less about “owning” in a capital/purchase-sense and more about internalizing knowledge and experiences. A (knowledge) domain of my own is a thing I have chosen to immerse myself in, to struggle to understand, to follow ever deeper. The domain name may come or go. The technologies will change. I may or may not eventually have a server in my closet but I’m making intentional choices that lead to greater knowledge. Knowledge that people can’t take from me. Understandings that are bigger than a particular technology or piece of software. A domain of your own provides you with the options to follow rabbit holes, to pry up floorboards, to paint a room, to see what happens if you mix a bunch of chemicals and set it on fire . . .