Those multiple levels have proved very powerful. When the big earthquakes hit Japan industry all over the world was quickly able to figure out parts of the supply chain was most critical, vs what could be sourced elsewhere. (as I recall all the pure silicon for chips is made in Japan, so those factories were given all the electricity needed, while other factories that had competition elsewhere had to wait to get the limited power left). Companies that had their suppliers traced out that far were able to work stay in production much longer than those that didn't find out until months latter when things got through all the levels.