Depends what you mean by "Building Automation." If you mean things like a thermostat to control my heating, sure that has been around for decades. However, it can be a very simple mechanical device. Even for the computerized ones, I see little advantage to networking it (at least compared to the disadvantages).
If, however, by "Building Automation," you mean networked computers controlling your lights and every other aspect of your environment, this is not the norm now, never has been, and I would hazard a guess that it won't be any time soon because the cost and complexity is not worth the marginal advantages. Yes, some elements are creeping in: particularly systems to shut off lighting and environment control in office buildings at night because the power savings are worth it, but those systems are relatively simple and closed. There is no need to connect them to the sort of network that is featured in the article let alone the internet at large.
Lighting systems are very common in the building automation industry but they're typically connected to physical switches. Placing a computer or tablet there doesn't really change things - this could have been hacked regardless of the end-user input. The core protocol Modbus/TCP has been available and easily hackable for decades.
Building Automation is exactly what your describing and it is the norm. It's common for schools, hotels, and commercial buildings to be "smart", with something like Modbus or BACnet connecting lighting, HVAC equipment, smart meters.
I will defer to you re: Modbus/TCP as it is outside my area of expertise. Even if these systems are "common," I would still claim that they are not the "norm" for the simple reason that I have been in buildings that were clearly "smart" buildings and ones that were clearly not, and the latter outnumber the former. However, even if it were the norm for commercial buildings, I was thinking far more generally and that may be the source of our disagreement. Automatic doors, for example, are the norm for major retail stores (as well as airports, et cetera), but they just don't exist in private homes. It would be expensive and serve no purpose, and that is how I feel about most "Internet of Things" devices [EDIT: and most "home automation" devices].
