We're not broke, and it's not that we "can't afford" the next-gen, high-end stuff. What we can't afford is the abomination of a procurement process we've got. Planes (and tanks, ships, etc etc) take much longer to field and cost much more than they should. The political games that go with buying any big systems nowadays are the real problem, not the systems themselves.
That being said, the author of this article is an idiot. These same pieces have been recycled since 1990 or so. Before they were short-sighted, now they're just naiive. It's like telling Britain at the turn of the last century that battleships were obsolete, since the Boers didn't have a Navy. Yet the peak of the Boer War, when the Brits were fighting lightly -armed insurgents, was only 15 years before Jutland.
Russia and China are building advanced weapons systems and, more to the point, selling them to even more unsavory characters. Meanwhile, our equipment is more than outdated, it's becoming dangerously old. F-15's literally falling apart in flight? We've become complacent in our role as sole-superpower, pure and simple, and it's going to bite us in the ass unless we get our acquisitions act together.