Facebook and other tech companies are a great example of what would have happened if AT&T had not been split up for monopolistic practices. AT&T would have become a middleman in all communications. Can you imagine having to pay AT&T and other internet providers a chunk of your on-line revenue? That is what Facebook, Apple, Twitter and others are doing.
The new monopolistic middlemen are taking a big percentage of the world economy just because they are providing the infrastructure needed to run business. They decide who can reach consumers and who cannot. It is not sustainable.