I think the the context of this statement refers to hiring, as opposed to choosing what language/platforms your team should build with. All other things equal,

I think the the context of this statement refers to hiring, as opposed to choosing what language/platforms your team should build with. All other things equal, for a startup, I'd rather hire a smart freshman over a middling candidate who had five years' experience with the language/framework I wrote my app in. Plus, there are a number of startups where the speed at which you can "build stuff" is not the limiting reagent towards success. Even if you were the fastest builder in the world, if you don't build the right product, no one will pay you money, and you'll run out of runway. (Dozens of student "startups" out of the University of Waterloo run into this exact problem during every four month term.)