The things you cite are pretty much all because I would never give 0% probability to a future event. Who knows? Things change. But I think it is quite unlikely that NaCl will become a widely accepted part of the Web platform, and I think that would be a bad thing in its current state.
My "highly pragmatic and specific" criticisms seem to me like they say the same thing as Brendan's original slide bullets, just with more detail. I did not mention "no view source", but I agree that is a significant downside, if not necessarily as much of a showstopper as the others. Being a single-vendor-controlled technology is the biggest showstopper.
Another big issue that I didn't mention, and which I think also aligns with Brendan's criticisms, is that adding a major new technology to the web platform requires tremendously compelling use cases and a good argument that they cannot be handled with existing technologies. I don't think that case has really been made for NaCl.
And yes, I did jokingly coin the term "ActiveG" to refer to NaCl. Though I believe it was another wag who later referred to Dart as "GBScript".