A look at the ownership structure may explain the shift - The Economist is now 50%-owned by big business interests
http://en.wikipedia.org/wiki/Economist_Group
BTW, they endorsed B. Obama for president twice, in 2008 and 2012, who has been, despite all the populist rhetoric, very friendly to Wall Street and big business (not a single Wall Street criminal has been indicted)
I still like them, for the excellent writing, but I find myself agreeing less with them over the past several years.