I got the impression that the underlying motivation for writing the post, and tactic you used for justifying your positions was largely in response to what I would consider the overly myopic hacker news user base. That is, disproportionately white, male, curmudgeoney programmers. I sympathize with your frustration, but urge you not to let their world-view cloud yours, or cause you to search for complicated answers to simple questions.
An example of what I mean:
> I believe the current skepticism around Silicon Valley's "Make The World a Better Place" mentality is deeply rooted in historical anxiety about institutional capitalism.
On this point, I urge you to consider a much simpler explanation: that people are skeptical because there is much to be skeptical of. People like Musk are a rare breed in Silicon Valley. Today's tech "entrepreneur" rarely looks like Elon Musk, someone who genuinely seems to want to do good things for the world. The skeptisism exists because there are a lot of startups doing plain silly things, masked in global do-goodery marketing narrative.
Startups are the new gold rush, today's investment banking. But the west coast has much different cultural norms towards opulent wealth than does the east coast. Put simply, we like to hide it out here, they like to flaunt it out there. Thus, "we're making the world a better place" instead of something like The Wolf of Wall Street.
Still, I enjoyed your post and your choice of using macro-economic theory as a lens through which to view this. Thanks for writing.