It's always a matter of taste when it comes to language design, but I'd have to disagree with this assessment ;-)
> which is necessary to build an artifact of this size without self-immolating
Well, that's certainly not the case. Plenty of huge software artifacts of very impressive quality have been built by non-language-designers.
> Another is that it is a commercial company following a plan
This is certainly true. Or rather, several plans, all of which intersect at common mathematical sub-questions. So then the entire company can leverage effort that's been poured into those components.
> A third is that few people have learned the lessons of Mathematica enough to apply them
Nah. I think the third reason is that Wolfram hires excellent hackers who are also excellent mathematicians. He hires a lot of them. And he puts them to work on the intersectional capabilities I mentioned above.
(Disclaimer: pure conjecture. I've never worked at Wolfram)
Others have tried to catch up, but they can't match the output of the engine he built to power Mathematica's development.
Frankly, it seems strange to me that he's not considered a folk hero on HN.
This is what separates successful from struggling.
Many relentlessly focused and driven people have failed miserably, and many vague and sluggish people have succeeded beyond all expectation.
Take me, for instance. I waffled along one step ahead of destitution for thirty years and then got an amazing job without trying even slightly. Now, I'm on track to retire before I'm fifty. Everyone who knows me calls me lazy! What have I done? Why me? I just give generously to charity and keep my head down.
I've found a crucial skill for a happy life is to carefully avoid pointless effort.