TCP/IP will never go mainstream. It is just a prototype. The idea that a protocol that was state of the art in the 1970s will be used by billions of people in the 2010s is just stupid. By 1979 the internet hadn't become mainstream so obviously it was never going to happen. Something more efficient than the internet will come along and we will use that instead.
So you want to go that road huh? Compare Bitcoin to any other successfull sites since the year 200. I could name Facebook, Myspace, Twitter, Spotify, the list goes on etc etc and want to know what all those sites have in common? They became successfull within a very short time and Mainstream. Bitcoin is supposed to be this new, next generation, of money handling, but has is a very long way off being adopted by the general public, who aren't programmers and tech guys. It's simply never going to get any higher in terms of popularity, too many flaws.
Not to mention you can't compare the Internet to Bitcoin..If you do research, you'd know Bitcoin wasn't the first virtual currency ever created, but the most successful thus far, at least in the tech and illegal community but not general public, especially because it's decentralized and anonymous(Perfect for Drug Dealers).