The main concern is that a company could come along and pump out all the water from an aquifer or lake that a village/community/town depends on and it would be

The main concern is that a company could come along and pump out all the water from an aquifer or lake that a village/community/town depends on and it would be perfectly legal because "it's my water too". Privatizing the water supply should be heavily debated and the outcome should be what is best for citizens. No price-gouging, as low as possible price for water, etc. Right now companies can dump chemicals into many public water sources even in the US because it's their water to use also. Industry and farms are the biggest users of water, normal people need to be protected from their abuse of the worlds finite fresh water supply. If someone invented a machine that sucked air off the planet at a rate which actually threatened the worlds air supply, then yes, air should be regulated. In fact, it already is to some degree with anti-pollution laws. Regulation and competition allow companies to exist, make a profit, and help citizens at the same time. Yes, some companies abuse their power but as long as government corruption is kept to a reasonable level then the government can step in and either make the company change (in numerous ways). There would be a problem if a private company had a private military that was more powerful than the governments military, I think that is the plot of the next Call of Duty game...