As Silver this year, I've been upgraded 5/8 upgradeable flights this year via EAU, and overall I'm pleased. (Doesn't include AS, HA metal flights, Y-Fare flights, Hawaii).

It may have to do with the days/times you fly... you may be consistently flying at peak times. Also looking at the markets you fly, esp. New York and Chicago, seems you fly with lots of other business types. If you're flying Y (I'd think so with $1,200), you should be upgraded automatically, or can kick co.com to do it for you.