Does closed necessarily equate with usable? I know it is frequently an argument put forward to justify Apple’s approach, but it seems like an example of “framing” to me.

That is, reduce the concept of “usable” down to one that is consistent with Apple’s marketing strategy (ie., it just works, it looks beautiful, etc.,) and then claim the high ground.

I don’t find Apple’s products exceptionally usable at all; they tend to have a nice user interface, but that for me is really only a very limited part of overall usability. A closed device that I can only have limited access to doesn’t really appeal to me as usable – it is something that should probably be more accurately described as “convenient.” And we all now what happens when you blithely trade freedom for convenience…