Well as I said in an earlier post, the very same day I got 2 new tyres which I was trying to argue about with the mechanic at the shop should go at the rear, but he was giving me the same arguments you're giving, the front does the steering and the power, it's more important to have a grippy front, bla bla, all the while having a Michelin guidelines for safety poster right in the garage, where it clearly said newer tyres should go to the rear axle!
In any case, off I went with my fresh rubber at the front and half worn tyres at the back. Driving 250 km back to college.
Obviously it'd been raining and the surface of the road was damp, and while taking an exit from a highway, a left turn as I remember, the back end just snapped away, no warning, no feel at all. Since I was young and rather unexperienced I tapped the brakes and tried countersteering, but it did nothing and because it was an exit it meant it was narrow and had guard rails at either side. So I crashed into the left one. Luckily it was mostly cosmetic damage and a broken turn signal & headlight, I was travelling at 40 kph at most.