Looks like he's talking about "small/new businesses in general" rather than "startups" in the more Silicon Valley sense of the term.
Yeah, I would guess that the needle is moved more by trends in people opening restaurants, shops, auto mechanics, etc. There aren't enough Silicon Valley startups with non-founder employees to account for a very big chunk of that 400,000 new companies per year figure. I believe VC-funded tech startups are only ~500/year or so, for example. Presumably angel-funded startups are several times that, but I'm not sure enough times it to be noticeable in the aggregate trends (especially since we can only count angel-funded companies who've hired non-founder employees).