In his analogy, we're the peasants who have traded in freedom for some convenience and protection.
Users pledge allegiance to more powerful companies who, in turn, promise to protect them from both sysadmin duties and security threats.
He sees the two big power centres of the feudal lords as data and devices.
On the corporate side, power is consolidating around both vendor-managed user devices and large personal-data aggregators.
We no longer have control of our data:
Our e-mail, photos, calendar, address book, messages, and documents are on servers belonging to Google, Apple, Microsoft, Facebook, and so on.
And we're no longer in control of our devices:
And second, the rise of vendor-managed platforms means that we no longer have control of our computing devices. We’re increasingly accessing our data using iPhones, iPads, Android phones, Kindles, ChromeBooks, and so on.
I see the right to repair as a means of resisting this. Allowing us to do what we wish with our own devices - including putting whatever software on them that we want.
One big omission from the article I find is that Schneier focuses on the disbenefits to the users of these devices and platforms - the manufactured iSlaves, in Jack Qiu's terminology. He doesn't mention (at least in this particular article) those exploited in the creation and upkeep of these - the manufacturing iSlaves. That's just as big, if not bigger, a reason for challenging these power structures.