What happens when individual companies are allowed to own and control the way your "smart" stuff talks to you and other smart stuff? It's walled garden time, all over again.
One important point that Phil's not quite gotten at in this otherwise excellent piece is that there's a whole world of "adversarial interoperability" through which you break open the walled gardens and put your own stuff in them. This isn't technically very challenging, and companies and organizations have a good track record of hacking their peanut butter into the walled gardens' chocolate, but laws like the DMCA mean that you risk jail for undertaking this noble activity.
My point isn't a narrow technical one. I'm not arguing for an open Internet of Things because of perceived technical benefits. Rather, this is about personal autonomy and ultimately human rights. As I said above, the Internet of Things will put computers with connectivity into everything. And I really mean "every thing." They will intermediate every aspect of our lives. Our autonomy and freedom as humans depend on how we build the Internet of Things. Unless we put these connected things under the control of the individuals they serve without an intervening administrative authority, we will end up building something that undermines the quality of life it's meant to bolster.
What is an "intervening administrative authority?" Take your Fitbit as an example. You pay $99 for the device, but cannot use it without also creating an account at Fitbit and having all the data from the device flow through Fitbit's servers. In this case, Fitbit is the "intervening administrative authority." Whenever you create an account at Fitbit or anywhere else, you're being "administered" and giving up some amount of control. That's not necessarily a bad thing, but it does, taken in aggregate, place real and significant restrictions on personal autonomy.
If Fitbit decides to revoke my account, I will probably survive. But what if, in some future world, the root certificate authority of the identity documents I use for banking, shopping, travel, and a host of other things decides to revoke my identity for some reason? Or if my car stops running because Ford shuts off my account? People must have autonomy and be in control of the connected things in their life. There will be systems and services provided by others and they will, of necessity, be administered. But those administering authorities need not have control of people and their lives. We know how to solve this problem. Interoperability takes "intervening" out of "administrative authority."