2209WA wondering about the design

I have a laptop, like many others I plug it in and disconnect it from my monitor daily. When I disconnect it: Why does the 2209WA say "no VGA cable" when a) there is a VGA cable still connected?
* Because there isn't anything sending a signal through the VGA cable connected to the monitor.

the monitor has a standby mode that would prevent it wasting energy and wearing the backlighting all night/workday? (I know it has a powerbutton, but that's only relevant if you're not in a hurry and remember pushing it after you notice that the screen won't go to sleep).
* But you broke the signal improperly by simply disconnecting the VGA cable from the laptopVGA port. Powersaving is made to function while connected to a computer. The people who decided on the designs do not come to these forums. They are not customer facing. To be honest, ALL of our monitors will state, "no VGA cable" if you simply disconnect the VGA cable from the laptop. Why? Because you were sending a signal to the monitor and then you stopped sending a signal. So the monitor says hey, what happened and throws up the no VGA cable message.

Why does the USB hub power off with the screen?
* The monitor and USB hub both use the same power circuit. If you turn the monitor off, the USB hub is off.

Am I expected to unplug up to four peripherals and plug them into my computer every time I want to use them when  turning the screen off (I have a habit of turning off screens when I leave the computer, e.g. while waiting for a USB transfer)?
* Yes.

First of all thank you for taking the effort to try to answer my questions. However, since your answers only gave the technical reasons and my questions were pertaining to (I might have been a bit unclear here) human interaction design reasons (for instance, it's obvious that the screen and the usb hub is using the same power circuit, but why is that better?) I'm still left wondering. I may break a signal "improperly", but it is obviously still detectable by the monitor (or there would be no "cable missing" message) so it could very well go into sleep after, say, 5 minutes. That's a reasonable time to debug a message like "no VGA cable". The question is why doesn't it?

If no designers come to these forums, so be it. I'm just trying to show an interest in some anonymous designer's work and finding out some reasons to (supposed) design decisions before blindly writing things off as design flaws. Everyone might not see this kind of (human interaction) design as a selling feature, I don't know. If that is the case here then I would be equally satisfied with that answer of course. If the designer wanted it a particular way but it was too costly then that is fine. I'm interested in the reasoning behind the behavior, and frankly I was just thinking there would perhaps be some designer that might appreciate a shown interest.