I think Bill Luther made a similar argument? Though I can no longer find the article that I think I read of his (there are many others, though.)

I don't personally find the regression critiques compelling bc I had always viewed it from the grounding perspective, which is basically what you said Murphy said: you can ground anything in anything. It gets really interesting in btc's case where in the very earliest days its value was basically grounded in some combo of lulz, novelty, and rampant speculation. But that was enough to get it started. Now we see the very first sprouts of circularity, though honestly those effects are themselves grounded in those other thing, too.

The most interesting extension of this is the example Lyn gives of monetization of that magical item in that online game (the name escapes me now and I don't have the book in front of me -- anyone?) I think @k00b linked a book on virtual economies that probably has a similar energy, though I haven't read it.

And actually, this is why I thought the Brave token was interesting: grounding the value of that token directly in human attention. (Well, that's the theory. In practice it was speculation, on the short term at least.) It's an interesting philosophical example of monetization, but hard to find anyone who wants to talk about it in those terms.