As I read the post in question, the aside about track-counts was really just a rough, conservative, rule of thumb. As is the case with rules of thumb generally, real-world results depend on lots of other variables.
I agree that the post seemed (based on what little I know) very well-founded and well-explained.
It's actually kind of refreshing for someone to be conservative about what digital audio systems are capable of ... manufacturers and assorted sellers are usually a lot more inclined to tell you all the great things their products would be able to do in an otherwise ideal world. While it's somewhat interesting to know what - say - a $200 software package can do in a $10,000 computer with another $10,000 of audio equipment, the practical realities are usually slightly different.