That is the topic of his column today, I had not seen this very good point before:
One possibility is that the numbers are missing the reality, especially the benefits of new products and services. I get a lot of pleasure from technology that lets me watch streamed performances by my favorite musicians, but that doesn’t get counted in G.D.P. Still, new technology is supposed to serve businesses as well as consumers, and should be boosting the production of traditional as well as new goods. The big productivity gains of the period from 1995 to 2005 came largely in things like inventory control, and showed up as much or more in nontechnology businesses like retail as in high-technology industries themselves. Nothing like that is happening now.
Overall Krugman is agnostic on the stagnation argument.