Was the old Mac a hacker's machine?

A recent discussion on the Well came around to the question of whether the classic Macintosh was “hacker’s” machine or not. Conventional wisdom would say no – it was the very definition of buttoned up. You couldn’t even develop software for it without a separate, more expensive computer (the Lisa) in the early days. But I think there’s a counter-argument to be made. Yes, the old Mac was a closed box that didn’t allow access to the internals of the OS.