This is nonsense. "Time for some new ideas, from people who actually grow complex organic systems: animal trainers." "Time for some new ideas, from people who actually keep large masses of people happy: sex workers." "Time for some new ideas, from people who actually clean up others' problems: garbage men." What your argument is missing is that even if top economists aren't great at economics, they might still be better at it than computer scientists. Maybe top economists are bad at economics because economics is hard. Not because only idiots do economics.
Computer scientists have proven themselves capable of going into completely unrelated areas (advertising, video, audio, hotels, taxis, airplanes, and most notably payments) and completely disrupting the status quo of the "experts".
And those experts were at least operating profitable legacy businesses, so had _some_ empirical proof of their claims (to wit: their products worked, even if not as well as the Valley's).
Now, lo and behold, we have a direct test of open source software vs. Krugmanesque proclamations. Krugman is simply not qualified to evaluate Bitcoin. You think he knows SHA-256 from a hole in the ground? He'll say it won't work just like legacy payment providers thought Paypal wouldn't work. And then he'll start advocating that it be prosecuted once it does threaten him, and then he will lose.
You are exhibiting a selective memory that only remembers the successes. Investors in the late 90s pumped money into "computer scientists" only to find that just because something is being done on the Internet doesn't make it automatically profitable. You look at Bitcoin and think it is so obviously Amazon.com, but it could just as easily be Pets.com.
The same way studying entrepreneurship doesn't make you an entrepreneur, studying economics doesn't make you an economist.
If someone can reliably predict macroeconomic trends and manage risk, what's their excuse for not being filthy rich? If they're not rich, I don't trust their tallent. If they are rich, I trust they won't give away their secret formula.
