Quote from : Physics of the Future: How Science Will Shape Human Destiny and Our Daily Lives by the Year 2100 Book

The real bottleneck is software. Creating software can be done only the old-fashioned way. A human -sitting quietly in a chair with a pencil, paper and laptop- is going to have to write the codes... One can mass-produce hardware and increase it's power by piling on more and more chips, but you cannot mass-produce the brain.