perhaps running them so hard is transferring the 'hit' to the rim,. instead of the tire absorbing the energy,.
I think if it were me, and i was ruining wheels on a regular basis,. i would look to buy different wheels and tires,.
Wheels and tires to match the environment i,m operating the vehicle in,.
Kinda like buying snow tires for the winter, instead of being out of control with the cool looking summer slicks,.