The article mentions power usage, and I would bet cost is also a factor - this is the reason many cheap SoCs only have USB2. One day I'm sure the cost will be low enough such that it will start appearing on "prosumer" equipment, then filter down.

However sometimes cost isn't the only factor, like in the case of two-pair gigabit https://en.wikipedia.org/wiki/Gigabit_Ethernet#1000BASE-TX.