Big Nerd Ranch was running boot camps long before the crop of web dev camps that came up in the last little while. It really was a way you could get into Mac OS X and iOS dev early on. Beyond that, it felt like the best way was to have already been an OpenStep developer.
Agreed - their books were/are inspiring. I think we need books more than ever for iOS and macOS since Apple's documentation doesn't seem to be as good as it used to be.
Closest I see is that “the landscape of tech education has evolved.” I agree but it would be interesting to hear more of their take.