When gmail rolls out an update, do you want to pre-approve it also? The only thing google does with chrome is bring the web model of automatic updates to a desktop app.
If you think about it, the only reason we want the control is because we don't trust software companies not to mess up our system. The crazy thing is wanting manual updates, because it implies gross incompetence from the software industry.
Well. Personally I see a whole lot of difference between web applications and code running on my machine.
In the case of gmail, I rely on their code only for checking/sending mail. And they have access to just my mail data. When something runs on my machine, I need to be a lot more careful about what data that code has access to and what privileges it has.
Since email is used to recover lost passwords, just checking/sending mail is equivalent to "the keys to every website I have an account on". By trusting Google to keep your email safe, you're trusting them to keep your entire online presence safe. In that light, letting someone run code on your computer seems relatively tame.
If you think about it, the only reason we want the control is because we don't trust software companies not to mess up our system. The crazy thing is wanting manual updates, because it implies gross incompetence from the software industry.