AFAIK the USB to Android connection is controlled by the Android. You send a MTP/PTP request from your PC, and it responds, kinda like an FTP server. What the Android will allow over the USB connection is very much up to the makers of the Android.

I think I should be able to use my Android as a modem, send texts, email, etc through USB and over the phone's connection while it's sitting beside my keyboard charging. Alas, it is not to be.

Android is very much wireless-centric. You can do all that wirelessly, but not wired. I even charge my phone wirelessly much of the time. I only charge via USB in the car. At home I just drop the phone on the wireless charger and forget it. I regularly use the phone as a wifi hotspot, and I can do pretty much whatever I want from a PC or wireless keyboard/mouse. All it takes are the proper apps, and they're readily available.

I'm an electrical engineer. The metal case is a wire.

Others use induction to energize components. In either case they still need to make contact web [sic: with] the terminals.

"web the terminals"? :-D

It's far from a USB cable, though. The case isn't metal, although there is certainly metal inside the plastic. Being pedantic isn't a requirement here, but it helps.

true, it just irks me a little. the only true wireless energy supply i really give credit to would be things like ics stickers / rfid tags which dont contain batteries but the circuits become active when they are a few meters of a transmitter.