Although Google seems determined to keep adding new features, I suspect there’s little it can do to prevent Google from becoming a ghost town. Google might not know it yet, but from the outside, it’s clear that G has started to die—it will hang on for a year, maybe two, but at some point Google will have to put it out of its misery.
Why am I so sure that Google can’t be saved? Because there’s no way to correct Google’s central failure. Back when companies were clamoring to create brand pages on the network—or users were looking to create profiles with pseudonyms, another phenomenon that Google shut down—the company ought to have acceded to its users’ wishes and accommodated them. If Google wasn’t ready for brand pages in the summer, it shouldn’t have launched Google until it was. And this advice goes more generally—by failing to offer people a reason to keep coming back to the site every day, Google made a bad first impression. And in the social-networking business, a bad first impression spells death.

Google had a chance to compete with Facebook. Not anymore. – Slate Magazine

I too tend to think that G+ won’t work in the long run, but I don’t believe Manjoo has identified the real reason. The real reason, as a million people have already said, is that everyone’s friends are all on Facebook.