I think part of the key is to have the direct democracy be digital/online. With needing to motivate people to go to the polls (like in California) advertising and money seems to play a large role.

I think a direct democracy will still need a president and congress to handle many aspects of governance, like military action, state secrets, etc. My hope would be though that a direct digital democracy would take some of the decisions away from congress and put those decisions in the hands of the people. But certain aspects of government, particularly the military and judicial system will always have to be centralized.