Instead of crying for LL “to fix stuff” (this issue is much more complex than that – believe me, if it were easy, it had been “fixed” years ago 🙂 ), some residents are abandoning the notion of in-world shopping, and relying instead on other ways to sell their products and wares. Web shopping seems to be one of the best alternatives so far. I hope that Linden Lab is following this trend closely (they certainly know about SL Exchange 🙂 ) and rethink their strategy for improving the rendering engine.
After all, at the end of the day, a completely different approach to the rendering engine is what will enable lag to slowly disappear. But don’t hold your breath – it is way difficult!