Back when IBM had an outlet store in RTP (at the Morrisville outlet mall), I asked one of the employees there about the keyboard and why it wasn't carried forwa

Back when IBM had an outlet store in RTP (at the Morrisville outlet mall), I asked one of the employees there about the keyboard and why it wasn't carried forward to new models. He said they had a lot of returns on them, as the cam that controlled the sliding-puzzle-action when the lid was opened wore more quickly than expected. It really was a unique design and got the Thinkpad line a lot of good press, so I think it was successful in that aspect.