1. Actually, this one is kind of easy. Market prices are based on supply/demand. Destroying things reduces it's supply. The more of something is destroyed in the free market, the more expensive it becomes, and the less people want it or are willing to pay for it. Eventually the market will get to a point where continuing to destroy some things is just not profitable any more. UNLESS we have a non-free market player, such as the government, deciding that some things are needed for the general good of the population, and subsidizes that good. Example is corn, which we use in many of our foods, which is subsidized to the point where it costs more to grow it than it's sold for, and which is screwing up our land with overfarming.
As for companies polluting, the bigger issue is the lack of a legal recourse for people to defend their property against polluting factories. I would argue that that's more a problem of the legal system than a free market.

2. People are greedy. They want things done to make them rich. If they are freely allowed to have other people work for them to make them richer, and pay those other people competitive wages, those other people will have money to buy food and not starve if they chose not to. That's not the case in Africa, where greedy free-market people are being kept out by greedy gun-toting people.