Is Felix Blowing Smoke Here?

Felix Salmon often knows what he has talking about.  But he's got a somewhat bewildering piece up  (I can't figure out his point, and I don't think he can either) about Vanguard v. Fidelity, which ends with this zinger:

As for Fidelity, it’s surely still near the beginning of a long, slow decline. The world of fund management moves glacially yet inexorably, and although Fidelity will certainly continue to make billions of dollars in profit for many years to come, its best days are now far behind it. Vanguard’s, too, most likely.

Huh?