Or because the loss of customers from gross chemical tasting meat that gives you diarrhea offsets the 3 cents per pound saved. Reminder that the 30% of meat or whatever is in Taco Bell's mixture could very easily be the sort of meat that is adulterated with pink slime but it is not. If they were interested purely in lowering as costs as much as possible, that would be an avenue for them.
http://abcnews.go.com/Business/taco-buns-fast-food-meat-cook-home/story?id=12826571#.T1xXwPVKV8F (I ignored the video) Here's a decent article from a year ago that mentions pink slime, fast food, and even hints at the pink-slime-pressed-steak method I mentioned upthread. The core of it is abotu how adulterants are pretty commonly used- but even then, a lot of fast food doesn't use them right now. And any adulterant that quadruples the rate of salmonella or e.coli is pretty obviously worse than, say, soy filler.
Regardless, there's still a huge, huge, huge, difference between ordering fast food junk and getting mystery trash and buying something at a supermarket and getting misleading mystery trash.
Ground beef has always included "mystery meat" including blood vessels, cartilage, and connective tissue. This really isn't new stuff, they just figured out how to get more of it.
As far as the whole Ammonia thing goes, it sounds bad, but the FDA recognizes it as safe. We've been using "pink slime" since 2001, and I've never tasted any ammonia in my burgers except for those nasty microwave whitecastle things, which barely have any beef anyway. For reference, I've had fresh ground beef that I'm sure has no slime in it because I watched it being ground. Ammonium hydroxide is actually fairly commonly used in food processing, and it even occurs naturally in beef.
The entire controversy is a carefully engineered media frenzy. The arguments against the practice seem to consist of "it looks and sounds gross" and "it has
chemicals in it". The only fact I've seen presented that worries me is the increased risk of salmonella, but the claims seem shaky at best:
School lunch officials said that in some years Beef Products testing results were worse than many of the program’s two dozen other suppliers, which use traditional meat processing methods. From 2005 to 2009, Beef Products had a rate of 36 positive results for salmonella per 1,000 tests, compared to a rate of nine positive results per 1,000 tests for the other suppliers, according to statistics from the program.
All we are really left with is emotional appeals, and very shaky study that shows a slight increase in risk over ordinary ground beef, which could easy be attributed to failure at a single plant or batch of beef. The media is playing into it because it sells advertising, and the fast food companies are playing into it because the public has been misled to believe the practice is unsafe.