I struggled at 1250 - 1450 for years ... always wondering how better players were able to destroy me. Then one day I suddenly found myself playing at 1600, and I really am not sure how it happened, other than to say I started paying more attention.
As for your 'autopilot' comment, I respectfully disagree. Perhaps they know a certain opening, and thus can play the first dozen moves or so without thinking much. But in reality, this is considered the "minimum" a good player should know! The real distinction of better players has very little to do with autopilot.
1800+