If they tried to force all manufacturers to produce all lead free ammo, it would collapse the industry. It is just not cost effective in manufacturing nor transfering that cost to the consumer. It could never happen, and if it did, I think we'd have been long on our way to taking back our country at that point.
Environmentalists recently tried to get the ball rolling with the EPA and lead bans again and the EPA basically told them no. I can't find the link, I read about it on PBB the other day.