Probably the largest disconnect is that while I heartily endorse simplicity and fighting complexity—even if it increases costs elsewhere in the system—I worry that we do not have the same definition of "simplicity". Rich Hickey's "Simple Made Easy"² talk lays out a great framework for thinking about this. I fear that they really mean "easy" and not "simple" and, for all that I agree with their goals, that is not the way we should accomplish them.
How "easy" something is—and how easy it is to learn—is a relative measure. It depends on the person, their way of thinking, their background... Simplicity, on the other hand, is a property of the system itself. The two are not always the same: it's quite possible for something simple to still be difficult to learn.
The problem is that (greatly simplifying) you learn something once, but you use it continuously. It's important for a tool to be simple and expressive even if that makes it harder to learn at first, since it will mostly be used by people who have already learned it! We should not cripple tools, or make them more complex, in an effort to make them easier to learn, but that's exactly what many people seem to advocate! (Not in those words, of course.)
So yes, incidental complexity is a problem. It needs addressing. But it's all too easy to mistake "different" for "difficult" and "difficult" for "complex". In trying to eliminate incidental complexity, we have to be careful to maintain actual simplicity and not introduce complexity in other places just to make life easier for beginners.
At the same time, we have to remember that while incidental complexity is a problem, it isn't "the" problem. (Is there every really one problem?) Expressiveness, flexibility and power are all important... even if they make things harder to learn. Even performance still matters, although I agree it's over-prioritized 99% of the time.
Focusing solely on making things "easy" is not the way forward.
¹ Perhaps it's supposed to be amusingly over the top, but for me it just sets off my internal salesman alarm. It feels like they're trying to guilt me into something instead of presenting a logical case. Politics rather than reason.