The fact that we still haven't found a way to use anything else easily after about 15 years and are still being somehow coerced into developing with it is what's surprising really :/
I recall that 14 years ago DHTML was the all the rage and javascript was the key to DHTML. So I took up JS and bought books and went in head first.
Conclusion: it was impossible to take that language seriously. Javascript was a hack.
So for me, the rise of javascript as anything more than a browser helper language has been very surprising. I still have some prejudice towards it. Maybe others feel the same way and knowing how O'Reilly comes from the UNIX tradition, I'm sure that's what they meant with that title.
That said, the development ecosystem around Javascript is very immature. To really write decent amounts of server-side JS as a team, people often employ linters and other things to sanity check their code. Debugging? Mostly printf's (or equivalent). Scoping rules can also be pretty annoying.
It is useful for getting things done, but it generally isn't my first choice (at least server side).
I suspect the toolchain will eventually get there, but it is a big step back if one is used to more integrated ecosystems.