The writer of the piece, Robert McCrum, makes this observation:
After Underworld, an 800-page tour de force, DeLillo's career turned towards the miniature: The Body Artist (2001), Cosmopolis (2003), The Falling Man (2007) are much slighter books, a rallentando that suggests a writer moving inexorably into the minor key of old age. Not that you'd find this in the demeanour of DeLillo.
I think the conclusion that small equates to minor key and a gradual slowing down is an odd one. I haven't read Point Omega yet, but I've read the three McCrum mentions here, and I don't accept that they are the work of a man easing into comfortable old age. They are challenging - intellectually and in essence. Like Saul Bellow, whose short fiction I mentioned recently, small can be profoundly complex.