Nothing is stopping you from starting a competitor to Google and Facebook.
However, you can not start generating electricity, put power lines on telephone posts around your town and begin selling electricity. Also, you can not drill a gas well in your back yard, and then go through your entire city and place gas lines in the ground and sell natural gas.
However, you can start an internet based company.
Wrong.
Unfair Software Patents are preventing you from competing with Google & Facebook. Monopoly.