Consensus was introduced by Satoshi Nakamoto, because Bitcoin removed the centralized decision making powers of governments and Banks.

Bitcoin actually manged to solve the Byzantine Generals Problem (Where the human element of trust and distrust was removed and replaced by technology) ===> "Proof-of-Work mechanism" 

The inputs are still from humans, but the decision making and consensus are done through a complex system of algorithm and math problems. This technology should be given a "Gold" medal for achieving something that has never been done before... but humans (governments and Banks) are still the problem, because they do not want a technology to replace their power.