That doesn't sound bad to me. I can't get 6 months out of a set of rear tires. That's ~8K miles of daily driving including an autoX of sorts in a nearby parking lot every few months to practice emergency maneuvers
Inherently, the tires that can last multiple years and lots of heat cycles are not the tires that are ideal for track or autoX driving, so there's a bit of a catch 22 here. Maybe try RE-11s next and S-04s after that if still not happy? You may just have to trial and error several tires to find the best for your situation.