I put about 10 hours a week on my trainer in the winter months and I don't find that my tire wears excessively. If you tighten the flywheel down enough, it shouldn't degrade. When folks don't tighten the flywheel down enough, the tire slips, causingthe rubber to degrade.

Tip of the day: if you go from road to trainer, clean your tire with a damp rag before riding the trainer. One little piece of glass that is on the surface will work it's way into the tire and puncture the tube with the added resistance of the flywheel.