All seasons are not snow tires...especially if they weren't kickass and very expensive. Obviously the fwd GP did better. I've driven a CTS and a G8, both rwd vehicles, one with quite a bit of power, for 7 years of winters with little issue. I've been stuck exactly 0 times. Again, you just need better tires. Your grandfather drove a 4000 rwd land yacht with no abs or traction control and made it work.