IBM, LAMP and rebuttal

Ryan Tomayko rebuked Daniel Sabbah of IBM's claim where LAMP cannot scale and the model should "grow up". He argued the traditional 3/n-tier design cannot scale due to its complexity, and a simple state-less design would be more scalable, faster and easier to develop. I am not really convinced, and I do hope that they do have some really really really fast object serialisation to keep very complicated data objects/relations always in the DB (instead of partially cached in app. server). And what if your fully-transactional DB is the bottleneck?