I can't think of any UI that is able to put all of its affordances on the screen at the same time. Even if you had the screen space, discoverability is hindered

I can't think of any UI that is able to put all of its affordances on the screen at the same time. Even if you had the screen space, discoverability is hindered by the sheer number of options. I don't think hamburger menus are worse than any other kind of menu. It's a symbol, much as "File" is now a purely symbolic word -- many applications don't have even metaphorical "files". You have to learn it, just as you once had to learn why moving the little doohickey on your desk moved the little pointer on the screen. TFA is still talking about hidden options. They've just replaced the menu with a sidebar. I suspect that's good for discoverability: menus disappear after you use them, while sidebars can be added and dismissed. (Though you now need to think carefully about what options you put on them, because real estate is limited on many devices and you don't want users to have to routinely add an extra click to dismiss.)