I've often found with most companies the unsustainable/unethical practices are often a lack of awareness and just the way things were always done, rather than a desire to rape and pillage the earth. They are still run by people, and most do care about what others think of their company (and not just the shareholders).

If it suddently becomes an important issue not to use palm oil (or at least not use very much), then a company will go to all of its suppliers and see if they can change to an alternative. Those that can, they'll consider and source the alternatives. Those that can't, they'll try to find other suppliers in the market that can make up the difference. It doesn't happen overnight (although it doesn't take five years, sorry Nestle!), but it's the start. Where palm oil might be necessary, the company can work with suppliers to find sources that are sustainable and work within their company to try to develop their products so that it's unnecessary. Nestle is already undergoing this process, let's tell them to speed it up!

It's about encouraging Nestle to change because it's the right thing to do and because their reputation is at stake. Any $$ effect on the company is so far down the line (and difficult to measure) that it's not part of the argument now.