Maybe. Or maybe this is just another plug - something accelerators are increasingly good at. It's becoming hard to figure out when an article, even in wsj or nytimes, is a hidden ad ("PR"), or genuine journalism.
500 Partner here: there wasn't any plugging going on here. I'd bet folks at the other firms mentioned will say the same thing as well.
This is a great development. Good accelerators create better networks for start-ups and are a much more useful time commitment for start-up founders. Too much of an MBA program relies on past information unavailable to start-ups. Accelerators provide useful skills in a compressed program that is much friendlier to starting a business than an MBA.