It seems like the author is saying two things. 1) The hold out method isn't robust enough and 2) There may not be much difference between the top performing models. Which, okay, there may be a point there. But that doesn't really support the thesis that competitions don't produce useful models. It's more like they don't produce models that can be deployed directly for clinical use. There's no reason the techniques used by the competitors can't contribute to something that is clinically useful.

Of course a title like, "Here's why you can't directly deploy ML competition models into a production environment" doesn't grab as many clicks.