Chad,
It sounds like a typical stunted bass pond. Genetics isn't helping you after 30 years, but I'd cull more LMB and stock mature BG before introducing any more LMB genetics.

I'm in the same boat as you (pun intended) with a pond I'm trying to manage at my mother's place. I can't get out there very often to monitor the results.

"Only after sorrow's hand has bowed your head will life become truly real to you; then you will acquire the noble spirituality which intensifies the reality of life. I go to an all-powerful God. Beyond that I have no knowledge--no fear--only faith."