Ummm, I disagree. That exact reasoning is why, for example, routers are being compromised on a wholesale basis.
If your washing machine is connected to the internet, you bloody better keep up with the manufacturer's updates, or your going to have some very funny looking clothes. Pretty much any router older than a year or two, that hasn't been kept up to date, is easy meat for someone who wants in. Similarly, there are reports of people using exploits to get into Tivo boxen, and running Bitcoin miners on them
.
Got a Jeep Cherokee? A recent one, with the U-Connect networked package? (BTW, I own a Chrysler. The U-Connect trademark *does not* mean the car is network connected, that's an additional option.)
If it connects to the network, somebody is looking to hack it. The only way for an individual or small business to protect yourself, is to keep up with those security patches. The bad guys are, and they're reverse engineering the changes to come up with exploits they know will work in many cases, because people
don't keep up with the patches.