If you give users the ability to go back and revisit a program with the idea of letting them save their work and quit, they will, without a doubt, abuse that privilege and pretend that they don't have to restart.
You put a time limit on that and threads like these will still exist, just instead with people complaining that Windows only gave them ten minutes to save everything before restarting.
Plus, if you do the thing where you check if the user has been active for the past several minutes, you'll have the same people saying "I left my computer on with my work open and it restarted wtf!!!!!" because you can't assume a computer not actively being used is one you can safely restart. (It's why they introduced the active hours thing--that's a far better way to judge if a computer's safe to restart because the user can define when not to restart the computer, but they're not allowed to set the entire day).
Really, complaining about the ticking timebomb--all software on the scale of Windows where most of the users fail to comprehend on how it works and how best to organize workflow to both stay secure and at high efficiency, you have to make the assumption that the user cannot be trusted and must be given as little ability as possible to create loopholes around stuff like this. Heck, I work at a division of IBM where we handle server software, and over the last few weeks we've had division heads continually reminding people saying "hey we still have servers with SMBv1 enabled why is this happening we thought we told you guys to disable it weeks ago" and those are people who write server management software for a living.
Like this is why I questioned your familiarity with software programming, you can never trust the user to work with you and install updates when they should or not insert sql commands into your online forms, etc, etc. That is something you learn very early on.
I don't think there's a single OS out there that can update every part of itself without restarting. Google's introducing something in the next version Android that might be able to do something like that? Not sure.
the win7 stans are almost as bad as the winxp stans back when win7 first hit the scene. fine the last windows release was a little rough, but refusing to update now that there's a better windows version out that brings forth updates you probably actually would make use of doesn't make you smart, it just makes you stubborn.