That's about recognizing there would be no mean reversion, a great indicative of the existence of crony monopolies and, therefore, lack of capitalism.
In American political terms, calling it an indictment of 'capitalism' is a little imprecise but not really wrong.
Goldman talks about "reversion to the mean", which is a generally-accepted thing in the financial world. If you've got above-average returns, people tend to take note, and try to get some of those returns, and so there's more competition for those returns, and that goes on until there aren't excessive returns any longer. This is a generally-accepted thing because it's been observed a bunch of times. It's the normal functioning of a market.
So if Goldman is questioning whether this is going to happen this time, it's a recognition that the markets aren't functioning the way they normally do - which I think is financedfuture's point. (He/she is going a step further, and [EDIT]implying that either the financial firms or the government broke the system that had been working, which, if the system historically worked and now doesn't, seems like a reasonable guess.)
> This is an acknowledgment our current "capitalist" financial system isn't able to produce "capitalism" itself.
That's a No True Scotsman argument intended to shield capitalism from any criticism. "The system isn't working? Then it must not be real capitalism."