I just received the same letter. Pretty much said, your very experienced but no thanks. My times are about the same:
6900 total
5456 jet
1575 PIC
5455 SIC
5680 Multi
8+ years of airline 121 exp.
2 type ratings
4 yr. degree
I'm gonna be furloughed soon from a major and I want to retain my recall rights so I put down on the app "no" when asked if I would be willing to relinquish my seniority from any airline. I'm wondering if that is what did it for me.