If you're thinking he could create a premium marketplace that works as a Wordpress plugin, it's a terrible idea. He'd be proving the model for Wordpress, as soon as he started getting traction they could introduce their own official premium marketplace installed by default in all new versions of Wordpress... and don't forget to upgrade for this month's important security fix.

I'm not a fan of the post's tone, but he's right that Wordpress needs to do it. Nobody else wants to try because they'd either fail or have it taken away from them.