Top footballers are already a physical elite. They're not just good athletes, they're some of the best. So for them to be intellectuals as well, would kind of make them superhumans.
A lot of footballers lack education purely because of the time in their lives when they have to make the decision to become sportsmen. It's not fair to label them as idiots because their sporting training necessarily precluded tertiary education. This is in contrast to rugby union players - generally the game is not played to any extent in state schools due to the level of expertise needed for the coaching. The top public schools and universities play a lot of rugby - hence that's where a lot of the players come from.
Some footballers are fairly smart, though - I seem to remember that Brian "Choccy" Mclair of 1990s Man Utd was a Maths graduate.
Fat Frank Lampard went to public school and was apparently something of a classics scholar. Isn't his daughter called Luna?
Ian Dowie (believe it or not) has a MEng.
There was a bloke that played for Watford who read Computer Science at Christ's College, Cambridge - but I can't remember his name.
Socrates was indeed a medical doctor (although he chain smoked throughout his career and even at half-time), but I've never heard of Shaka Hislop working at NASA!
Senderos at Arsenal speaks English, Spanish, French, German, Italian and Portuguese.