I am not expecting non-F8500 Samsung plasma derivatives to be getting anywhere near the F8500, they already have reached it with the F5500. I'm just saying, while they've reached the limit MLL-wise, they could still do further tuning. (Reducing the floating black further, Stop the rising black, making it go brighter, etc)
Heard from the news Samsung SDI is really having trouble with their plasmas because of higher currency value and Panasonic's departure from the plasma market. When Panasonic was still in the game, the subcontractors could still enjoy an economy of scale despite the shrinking plasma market, and now with only two left, they're a lot less enthusiastic about continue working with the Koreans. It's just like what happened with the RPTVs. When Samsung pulled out of the RPTV market, Mitsubishi was not in a position to be really happy about eating into Samsung's potential customers.