Earlier quoted context omitted.
I don't think you're missing much. Yeah, the main point seems to be that if your language has closures, you suddenly can express a lot of things that were out of reach before. Not a new insight. But there's another point I think that is hinted at on the topic of control abstractions. Or at least I'm reminded of the topic. It's better and more succinctly and explicitly talked about in an early chapter of the free book…
There's an upside to C's limitations. Several times I've seen expressed the notion that "every big Lisp project uses its own dialect of Lisp". This is less true in C, I think, because it doesn't have the power (ignoring preprocessor abuse, which does happen, see Bourne shell source[1]). C++ has a bit more power, and there we see projects tend to use their own subset of C++. In both Lisp, and C++, taking some isolated…
It may be, but even so, C is famously unreadable to the extent that it's a common observation that people can't read their own code from a few months earlier.
I think there is an argument -- one that would be very unpopular among Lisp folks, I suspect -- that says that for languages to enforce some forms of simplicity would help their uptake and use.
Most language advocacy revolves around poorly-defined notions of "power" where more power is seen as desirable.
I think Niklaus Wirth was on to something when he took the ideas of Pascal and kept simplifying as well as improving: Modula, Modula-2, Oberon, Oberon 2, and finally Oberon-07. (There are more -- Active Oberon, Zonnon -- but Wirth had retired by then.)