I thinks the salt used for melting the ice, the high variations of temperature, the surface being wet non stop for weeks when the snow melts and the frequent snow plowing (which is a huge metal shovel that scraps the pavement) contributes a lot to the fading.
I fucking hate cars too and I agree with you they are completely inefficient. But paint on pavement in cities where the temperature is near 0°C a good part of the year is also inefficient.