I think that the conventional wisdom about the poor durability of the Zoom-X foam is driven in large part by what people could see with their eyes: The VF midsole gets creases on the side immediately (it often comes out of the box with some creases), and the outsole has a lot of exposed foam that starts shredding right away. This makes the shoes look like they're falling apart.
But in my experience and that of most people I know, they actually feel pretty good for a few hundred miles. They're definitely not a one-marathon shoe. I get new shoes for every marathon anyway, but I wear the old VFs for other races and for key workouts, and they still feel bouncy. I do think the Zoom-X is RELATIVELY poor in durability compared to other foams (especially TPU foams like Boost, which last far longer than the outsoles and uppers of most shoes), but they aren't dramatically worse.