On a spectrum PC I could easily control six tanks and six planes to invade an island.

That only had the one building to capture and four turrets imagine the power of todays computers and what you can do.

No..... not the comfy chair!

Because tanks are a very vulnerable, combined-arms-only kind of weapon. They also tend to suck in city combat, as well as in woods or mountains. (Afghanistan is more mountains than anything else IIRC.)

Camera resolution only makes this problem worse. Human eyes not only have great resolution, but saccades (involuntary eye movements, that most people aren't even aware of) are used to interpolate an even higher resolution image from multiple samples. Sitting in your comfy chair and getting a 640x480 stream (I doubt that you could get horribly much more bandwidth when you have to relay multiple views from 2-3 tank brigades simultaneously) just begs to not be able to see that bump in the road which is a landmine, or conversely to not be able to tell if those round metal things in your path are mines or manhole covers.

But, anyway, tanks + infantry (and also preferrably AA and air) support FTW, tanks alone FTL.

So if you want to send robo-tanks in Afghanistan, you also have to send a few thousand droid soldiers with them.

And we all know how _that_ ends. Next thing you know some kid flies his fighter in and destroys your droid control ship's reactor, and your whole droid army shuts down ;)