It's easier to score a header if you have two feet planted on the ground than if you're jumping. Players like Crouch trade chance of winning the ball for accuracy.
And it works. Only Cahill has scored a higher percentage of headed goals in the Premiership than Crouch.
Well you've noticed two things, someone who doesn't stand still and climb all over the player has a higher percentage, and because of who Crouch is and often who he has played for, teams give Crouch more crosses to head in than they would Defoe.
The real question is how many shots with his head has he made vs goals with head, compared to other players, and that number is likely not impressive.
Every "great" header of the ball I've see is someone who attacks the ball on the run with a lot of momentum, standing still the pace of the shot is mostly dictated by the pace of the cross, and a slow cross is very hard to score, because even accurate the keeper/defenders have time to get across the goal.
When Ramos comes in at full speed and whacks the ball, it can be half a foot from the keeper and they still don't have time to react.
Its MUCH easier to score when moving fast and in the air than standing still.... not least because you're much harder to make when moving and much easier to put off when standing still in the box the whole time.
Seriously though, a HUGE portion of Crouches headed goals shouldn't stand because he's fouled to win the header.
Him and Kevin Davies, no idea, the latter fouls more than anyone else in the league, usually with double the fouls of the second worst offender, yet rarely(for the number of fouls) gets deserved yellow cards and deserved second yellows for repeat offending. Crouch is somewhat the same, he should get carded FAR more than he does for fouling and cheating in the box.
The one thing I'd say in Crouch's defence there Baz is, Crouch is built like a wet paper towel, if he tried to play like Shearer, he'd have probably had dozen's of injuries throughout his career, he doesn't have the strength or build to take repeated hard knocks.
That is ultimately the problem, above a certain height the vast majority of tall guys end up lanky, not build that well, have less good balance, a lot less speed and physically couldn't take the hits that Ramos/Terry/Ronaldo do when they run into the box from a corner at full speed. I don't think Crouch can do more than he does, he's made a career out of idiot managers thinking he's a better option than a real striker, which he isn't. But a guy with his build is playing really the ONLY way he can.