It's less about spying and more about planned obsolescence IMHO. They'll stop supporting your smart gadget after a couple of years and half the shit stops working.

Edit:
Same reason why wireless anything in your home is crap: someone will find a vulnerability at some point, usually after the vendor ended support.

There was another wlan hack going around a few months back that affected tons of consumer routers and access points. Most never got an update.

Smart and wireless gadgets all come with a hidden best-by date.

It's less about spying and more about planned obsolescence IMHO. They'll stop supporting your smart gadget after a couple of years and half the shit stops working.