One of the arguments used to support the adoption of lean techniques in software is the success of Toyota. So do Toyota's recent quality failings undermine the case for lean software development?
One answer for this is to take a sense of proportion. Lean manufacturing techniques were the underpinning of Toyota's rise from an insignificant company in the 1950's to a global giant in the 2000's. By the 1990's other car companies, and many other manufacturers, were busily copying Toyota's techniques. The general sense is that copying these techniques did much to raise the overall quality of cars in the last decade or so. I would be very surprised if the recent problems at Toyota are enough negate that half-century of success.
But a better answer is to remember that Lean manufacturing is about manufacturing not software. The application of lean ideas to software development is a consequence of MetaphoricQuestioning. Lean ideas can help us come up with better ideas for software development, and as such are valuable. But in the end their usefulness lies with how they are used in software and they should be judged on their record here. Their history in manufacturing, both good and bad, is another industry.