The fact that tournament big bass weights are falling at West Point Lake may make sense. A reservoir goes through a natural boom and bust period. When WPL was turning out its biggest bass, it had probably crested the boom period as a new reservoir. Now it's older and more settled. While there are certainly some giants in the lake, they're probably not as easy to catch.
As a former Georgia resident, I can also tell you that WPL has been going through some other changes associated with age. It's getting clearer, less turbid and less fertile. As a result (and I don't mind being corrected by any biologists who would care to comment or confirm), it's becoming more of a spotted bass fishery. Whereas spots never hit the scales in a tournament there back in the '70s, now they're common and will be growing more so as time goes by.
It's all a part of what I call the "spotification" of American bass fisheries. We're just not building many big new reservoirs (though small water supply lakes are popping up everywhere and often offer outstanding fishing), and our old waters are turning clearer and less fertile. That makes them less friendly to largemouths and more conducive to spotted bass. West Point is a great example, but there are plenty of others all over the country.