Big companies in Japan offer lifetime employment because they stay lean. They outsource almost everything, unlike the big 3 auto companies in the US. Rather than layoffs they simply buy less from their suppliers, forcing THEM to do the layoffs. The suppliers pay lower wages and most certainly do not offer lifetime employment. If a supplier pays his workers a little more or offers better benefits that force prices up a bit Toyota, Honda and the others just get a new supplier and the entire company goes belly up.
If the US automakers really want to emulate the Japanese they would outsource 90% of the actual manufacturing, stick to assembly, and let the suppliers deal with the layoffs and pay their workers squat.