that’s why I’m making my language as big and poorly specified as possible:
Common patterns in functional languages are considered "too clever" in most workplaces. Because they leave new hires dumbfounded and no one has got the time to explain them how to do their job. It's not that they're too "clever" but rather that the average coworker is too "dumb". But that's not a jab at anyone in particular, it's a consequence of our work culture -- and "clever" and "dumb" are not statements about intelligence, but about experience and team composition.
Basically the incentives are actually opposite to each other. It takes a long time to wrap your head around languages like Haskell because you actually have to know some theory, you can't just wing it. Javascript however...
On one side of the spectrum there's imperative languages and on the other end there's declarative ones. So this dichotomy creates friction and inertia.
I love Lisps, but for most companies, it's not the right investment. People don't leave school knowing lisp, its flexibility can be a downside with inexperienced developers, and it doesn't have the kind of ecosystem something like JavaScript or Python or Java or even C++ have. Nor can you easily hire contractors to help you on a project or to help clean up a mess.
Businesses like solutions that can be planned for, that are easy to hire for, that one can get help with if things go badly.
As for those who believe their language of choice can actually become mainstream, it's a long, soul-crushing and miserable road.
Understanding what kind of things people will build with you language would probably help, so you don't waste time trying to please people who will not use your language anyway.
I think the more likely scenario in a counterfactual world where Shen and Forth are difficult to implement is not that we have more things written in Shen and Forth, but that we have strictly fewer reasons to talk about Shen and Forth.
I am not convinced that the group that builds implementations and the group that builds the kinds of things that beget ecosystems for anyone other than compiler developers actually have much overlap. I do, however, think there is a strong overlap between the group that builds implementations and terminal-stage new-language addicts. An ecosystem for other things will maybe happen later if there's some other value to the language.
Where I think the article does hit on something is slightly less direct: users are more tolerant of a messy specification than implementors. C, C++, Python, Java and all the other languages that people actually use are ugly as sin at a semantic level, and yet we get by with copious handwaving. There are many problems, of course, with some of the handwaving users do to reason about these languages (hello, many warts of C), and generally, a preference for spec a user can keep in their head is a big productivity win, but if you want a language that people can use, you can afford to make your language a bit more complicated.
TL;DR: idk, make your pretty language with a beautiful spec if you want. Most languages are unused anyway. But there probably are diminishing usability returns for maximal spec beauty. If you care about that kind of thing, that is.
(Though I bet an optimising compiler would be a _little_ more complicated) ;)