The LPARS conundrum

Whenever you talk about technological advancements in operating systems in Solaris, you get the “But IBM has LPARS”-comment. Besides of having such a technology with LDOMS now and with XEN in the future, there is a major conundrum in this: How can a techology eating away up to 40% of your processor (IBM self-admitted in an withdrawn red book) have such a huge success as an emotional sales argument?