Why does my back tyre wear so much more quickly than the front? Identical tyres, identical rims, minimal braking on the back wheel, no skids, properly inflated at least once a fortnight to manufacturer's recommended pressure. Why does the back one wear out more quickerly than the front?

I suspect that "squirm" has something to do with it. As you pedal, the rear tire is forced first left, then right, slightly out of line with the direction of travel. (The front tire, OTOH, gets to pick its direction and force the rest of the bike to follow.)