With great power comes some responsibility

I got a chance to flip through a few pages of "The Walmart Economy" and a couple of things that tended to stick out were , Walmart had tremendous sway over its suppliers and that its margins were shockingly low(niether observation is earth shattering I am sure).
But it got me thinking about how Walmart could influence what the consumers bought.
Take the example of CFL's over regular light bulbs. Nations such as Australia are actually moving lesgislation in this regard(based on a quick googling effort)
Since CFL's use 66% less electricity then incandescent bulbs. Now figure that into the number of times the average individual forgets to turn lights off.
I am not trying to make the case for CFL's since I think this is a well beaten path.
Consider for a moment the propostiion that Walmart simply chose to stop selling incandescent bulbs in favor of CFLS's(In concert with other huge retailers)
Would't this go a long way in ensuring millions switch to CFL's?
Its all well and good to offer people choice and let them decide , but just as we have come to the conclusion that smoking is injurious by way of second hand smoke, why can't we agree that a individual's injudicious environmental choice affects us all?
So how about it Walmart? Would you be willing to discontinue one of your thousands product lines 3-4% margin for the greater good?
And how about it Target you think you can chip in as well?