I think Sony's expecting people to not catch onto their little scheme here... They discontinue the models with full BC, then introduce one with none, and now they're planning to discontinue the one with limited BC too? Those who plan to get a PS3 at some point (hopefully when it's less than $400 for a full-featured model; I'd go for $200 at most myself, given the current PS3 lineup), don't give into their scheme, or you're just forfeiting your power as a consumer over the supplier. Suppliers are supposed to provide to meet demand, not force consumers to consume the supply with a threat that it will be replaced by an inferior product.
Let them run out of 80GB models in due time, and when the 40GB model isn't flying off shelves, they'll inevitably introduce (or re-introduce) a model with BC to pick up the slack again. And then promptly discontinue it to try and scare people into buying a PS3 with BC, just like they did with the 20GB and 60GB discontinuations. If that's not their plan, then they've certainly done a good job at making it seem that way.
Sky Render - Sanity is for the weak.
