The problem is that it could be just one human. One person could own all of the machines. They would advise him, protect him, and carry out all of his orders.

Just imagine the President having his entire White House automated. The NSA? Automated. The military? Automated. Police? You get the picture. Robots and computers replacing everybody. One person in charge. 100% loyalty. Small pockets of resistance trying to hack into and take over robots, data centres, etc. Vast computing resources under the ruler's command employing all manner of encryption, fuzz testing, logging, surveillance, etc. in an attempt to eliminate the resistance.

It's like the plot of the Terminator movies without the general AI in charge. Instead, it's a legion of special purpose AIs serving the one guy.