The official average at the moment according to the DSA's figures is somewhere like 45 hours of tuition to pass. That's an average, however. My instructor trainer had someone who passed first time with a clean sheet after only 12 hours tuition from total scratch. Simiarly, he's had people into the hundreds of hours who still make fundamental errors when not fully talked through their driving every step of the way.
I'm teaching someone at the moment who's had 16 or 17 hours and isn't anywhere near close to me being able to keep quiet and let them get on with it on the approach to junctions or hazards. On the flip side, another student of mine was driving relatively safely and independently around quiet roads by their 3rd hour - they just "got" the car control, made good decisions and could judge junction approach speeds, meeting oncoming traffic situations etc.
I'd say that most people who have the interest and inclination to be on a motoring forum are going to be better than average, and also, have a different perception of how easy learning to drive is after their own experience.