Also, splay trees turn every read into several memory writes. Maybe not a good idea if the data structure is read by multiple threads (cacheline ownership bouncing back and forth all the time, rather than each core having it's own cached copy).
Binary Trees are a bad idea from the POV of cache use, and from your analysis, Splay Trees are much worse. However, this has nothing to do with the generalized meta-strategy of continually reducing the amount of work it takes to fetch items. It has to do with why Binary Trees are bad from the POV of cache use.
