Why does Windows Update still require rebooting?

Linux has long had the ability to patch the kernel while the system is up and running, so why can't Windows? Heck, if Microsoft could get the rebooting down to just the major March and September updates each year, that would be a huge improvement already.

 

Rebooting helps to load the drivers again and sys files to reload newer running version. Restarting or Rebooting helps in more then just updating running sys files but to insure installation is correct and functioning. After that you can leave it running til it drops dead. I go the safe route of Updating and rebooting to insure System Stability-I rather have stable running system rather then a sudden Fault and losing all my works in the process.

 

Because some files may be in use and need a reboot to be patched. That's why after you reboot, you see Windows Update animation and a percentage showing the completion of the update. Not a big deal to me.

 

Maybe it's the distribution I use, but whenever I have had new kernel updates, they were all installed, but required a system reboot in order to be used and become active.

 

If I remember correctly and it was few years ago, one of the advertised features of then brand new Win10, was promise of system updates not requiring reboot. Later I think MS backtracked a little saying, no reboot most of the time, but some updates will require reboot still and that's how it is now. Personally I reboot all my computers all the time, so no big deal, but I'm still waiting on that original promise,

 

There are few things that doesn't require reboot such as, regedit based tweaks works by restarting windows explorer.
Ubuntu Live patches needs you to login to ubuntu account otherwise you will have to update the system with a reboot.