Two words: Duverger's Law.
In a first-past-the-post electoral environment like the US, there is room for only two parties. Now, if you want to keep a multi-party environment, you would have to go to proportional representation, which would break up the Bit Tent parties into the Social Democrats, Liberal Democrats, Conservative Republicans and Religious Republicans, as well as the Libertarians, Greens, and sundry secessionist parties.