I don't read up on the updates of the apps I have, but I do get updates fairly often (updated three times in the two and a half weeks I've had the phone). Maybe it's a case of not leaving the wifi on for long enough (since it disconnects when it locks). I don't know how valid this is; I'm just giving you ideas.
With 200 apps I get updates often, almost every day. For me it's usually twice a day; at noon and midnight, in the US on the East Coast. But each server may be different.