Infinitely More Layers

In Hilton Als review of Sondheim's latest (long story short--book problems), we get this:

Although Sondheim began in a similar vein—think of the sentimental, sometimes weak lyrics that he provided for “West Side Story” (1957) and “Gypsy” (1959)—he quickly found his own voice, which was infinitely more layered, more urbane, more marginalized, and more dramaturgically brilliant than that of his predecessors.

"Infinitely more layered." You see this use of "infinitely" all the time now, and I'm tired of it. (I'm ignoring the shot at his early lyrics. Sondheim might regret not writing for character, being a bit purple and occasionally creating a real mouthful, but those songs still hold up.) What Als means, presumably, is considerably more, or even incomparably more. But when did it happen that people started using infinitely to mean a whole lot more?