He's not wrong. Nobody is spearheading their great startup app idea on the Windows platform. It's still very much iOS all the way, with a pinch of Android on the side if there's enough manpower to dev for it.
Microsoft needs to win people over to WP and Windows in general. They could easily write an Android compatibility layer for WP (as Blackberry did but do it better). Microsoft could also be giving out dev grants for good apps to jumpstart the market. But I haven't heard much from them. Previously Microsoft has never had to worry about a stagnant app ecosystem since Windows was so huge in the consumer market, so I don't have much faith in that Microsoft has the expertise to win in the app front.
edit: also, if Microsoft really wants to get high sales for the Surface, they need to make the damned thing cheaper. I can get an iPad Air for a few hundred bucks, or I can get a Nexus 7 for even cheaper. They would make a low/mid end surface and sell it at a loss if they cared about marketshare.