I may be wrong about only one person reviewing a product but that's pretty much Valve's way of doing things when it comes to not making video games. The "Valve employees don't really have bosses" is based on inumerous Gaben interviews (he's said multiple times he is the only boss there and employees have certain freedom to work). Lack of management would help explain Valve's horrendous Support.
We've seen games being rejected simply because
"Steam is not a good fit for distribution" (at least explain why you are rejecting it, Valve!), accepted after many attempts (eg SPAZ) and stuff like that, which is why I said the review process is terrible.