I'm guessing the decision to kill the regulation was not made after a careful cost-benefit analysis with consideration of alternatives such as government stockpiling, assuring supply chain surge capacity, etc.; it was probably part of a general purge of pending regulations (easier to kill them than to undo existing regulations) based on the philosophy that:
government regulation = usually bad
government regulation promulgated by the Obama administration = incredibly bad without question.
government regulation = usually bad
government regulation promulgated by the Obama administration = incredibly bad without question.
