It's quite funny because a group of my friends used to call ourselves the mercenaries because we had no loyalty to any existing company, and would leave in a heartbeat if the project was doomed or a bad manager was drafted in.
But there was also an element of guild behaviour in that anyone who found themselves in a good project/company tended to bring in others.
I think this is what the author was trying to convey, and the article does a fairly good job of providing information from and insiders prospective, even if it does objectify developers. I think most developers move between the two, what you stated seems to be very normal and 10x'ers seem to pick up other 10x'ers along their way. I have about 8 guys in my (guild) now and we float in between contracts and start-ups. I am working on funding of our next venture and I will be calling them in. When I do, they will come and that is very hard for someone on the outside to understand. Our dynamics work very different than other industries and it is very hard for people outside of it to understand. That is probably the think that I think made Steve Job's so formidable was his understanding of the dynamics of creative employees.
But there was also an element of guild behaviour in that anyone who found themselves in a good project/company tended to bring in others.