Bullshit. An incorrectly designed PCV system that does not have the capacity to adequately ventilate the crankcase will also cause the engine to sludge up.
Quit making excuses for Toyota. Is it an amazing coincidence that all of the lazy owners who don't maintain their vehicles just happened to buy the 2.2 and 3.0L engines from Toyota? I don't think so.
Toyota hasn't been the only auto manufacturer who has produced sludge-prone engines before.
Ted