Gary,
Yea, I can tell you what's wrong. The Treadwear Rating on your Yokohama A520 tires is
180 
They aren't made to last long. They give excellent grip but that's all. They weren't made for touring and I'll bet the other tires you had were the same way. Always look for the Treadwear Rating on tires for a street driven car before buying. Yo want something in the high 300's and 400s for decent lasting tires on the street.
Here's something to read....
Treadwear rating - Wikipedia, the free encyclopedia