it's about the economics of mining _using an external source of capital_. the more significant interaction is not between the ASICs and the bitcoin rewards, but the companies and their investors. in that sense, it's more accurate to say it has "everything to do with public stock markets".

the author gives the oil analogy. the oil wells themselves have very similar economics to mining. it's the relationship between these similar operations and the investors which sets them apart more than the activity they're involved in.