Because of legacy and backwards compatibility problems. It's like, when you have a database engine written in Cobol and you're asked to improve it by implement

Because of legacy and backwards compatibility problems. It's like, when you have a database engine written in Cobol and you're asked to improve it by implementing latest ideas in database technology, sometimes that code base is written in such a fundamentally broken way that a better solution is to write it in C. The problem with improving current system is that the system has all the power and will resist change. The people who can change the system are people who're benefiting from the system being what it is. It's not like there aren't people aware of the problem and trying to change it (see Lessig) but they are not having much success. The laws are created by Congress and many see corruption of Congress as the main problem and Congress will not vote itself from the island any more than Kim Jong-Il will. Which is why the only realistic way to really experiment with new governance systems, especially ones with radical ideas, is to start from scratch.