Trouble is most footballers say the same things due to their limited intelligence
I think that's slightly unfair. Let's knock out:
1) The things they can't really say in public tempting as it might be. Slagging off team-mates, the manager, the fans & the chairman are generally seen as off limits. (even if justified)
2) Those questions about the upcoming game/promotion/avoiding relegation chances: They can't say "No, we reckon Leeds will cane us, their squad is much deeper than ours and Tresor Kandol scares seven bells out of me. That'll screw whatever play off chance we have too so it's mid table for us"
3) They won't say too much tactical stuff either in a trade secret kind of way.
So given the consequences of saying anything controversial, negative, interesting or indiscreet can you blame them for trotting out a few cliches safely and retiring to the bar?
It's true most of them aren't about to quote Greek philosophical texts at you (though I bet Chris Blackburn could go off at a few tangents) but it's not down to having the IQ of a walnut in many cases.