Isn't a major issue with IoT always going to be security?
Let's be generous and assume that there are no known issues today for the "thing". Some issues are only evident when general technology moves on. For example, the system may be well designed and can't be cracked today but what about with the computing power available in 3 years, 5 years, or 10 years?
Who wants to spend time managing a "thing"? I'm not keen on the hassle involved in updating my computing devices (although I do) - it's a hidden cost of having the tech. That's worse for "things" that I expect to just be there and work. Even now, who wants to go round round the house checking that all network connected devices are running the latest firmware? TVs, PVRs, disc players, music streamer - do you check them all? Even if you do, does the latest update even patch the latest known vulnerabilities? Have you checked? For every connected device?
What happens if the solution requires different hardware? For example, perhaps the encryption is supported by a hardware module - what happens if the algorithm is found to be compromised? Will the vendor update the hardware of a 10 year old "thing"? What about if it's 5 years old? 2 years?
The whole point is that it's the Internet of *Things*. I tend to keep my "things" longer than I might keep my computing tech. A large installed base of ageing kit is a big support burden. That's likely to be complicated by the hardware being optimised to minimise production cost and further complicated with the design evolving over time as components are changed or eliminated. How long will updates keep being developed and issued? Supporting the ageing Windows XP is going to look simple in comparison.
Will every consumer be expected to become an IT specialist just to ensure that the "things" are all suitably connected and protected? Is that realistic? I don't think so.