If they'd intended to shut this down, they would have a locked down boot loader like on iOS. Instead they deliberately built a boot loader which supported things like this.
That can be changed in a software update. Is this likely? probably not, however I can imagine scenarios (lets say a worm gets out) where it might "make sense"
The action isn’t unprecedented. But that’s a separate company. What has Apple done to make people expect this behavior when they’ve not done it before?
This took time and resources to make happen. This isn't some switch a rogue engineer pulled while management wasn't looking. Not only did it take time and effort to implement, they've also documented it.
> When have Apple been open about anything recently?
Darwin, WebKit, Swift, LLVM, This effort.
Apple keeps iOS fairly tight the Mac, not so much.
That hasn't been their MO, historically. On macOS everything that's locked down by default can be unlocked (at least that I've encountered) regarding running software or other OSes on the hardware. They've made it "secure" by default, but not locked down, it's a simple switch to open it up.
If, say, the iPad or iPhone had gone this route (started off as open as Android and then became locked down) you might have a point. But they didn't, they started off restricted and have only (gradually, and to a limited degree) been opened up.
> Get people on board first. Lock it down once it's too late and everyone is invested.
Examples? Been using the Mac for 15 years and haven't observed this myself. iOS was more or less locked down from go, but they never did some kind of bait-and-switch.
If they'd intended to shut this down, they would have a locked down boot loader like on iOS. Instead they deliberately built a boot loader which supported things like this.