Warning! No science here and very little maths! Until recently, I had 3 springers. My vet, when I regularly brought them in for an injury, told me 3/4 of injuries he dealt with were springers.
Those talking about crashing through bushes, it's a spaniel thing. It's called going through cover. It's a much prized aspect in the gundogs world. They say that spaniels go straight through, Labradors go round. It's true, I've seen it time and time again.
I feel bad for my boys, they have had multiple tail injuries (worker was docked, pet bred aren't, guess which ones have had tail injuries) and one dog is on his fifth dew claw injury. Had he had his dew claws removed, that would have been a one off. Instead, he's been through five lots of split claws/suffering. There have been so many tail/dewclaw injuries that we've stopped taking them to the woods and they get training in a nice flat field instead.
If a gundog breeder didn't dock a litter, he'd have trouble selling. Then we'd lose some breeding lines and the co-efficient is already frighteningly high in the UK.
Yes, tradition is an entrenched part of docking, of course it is, BUT it also has a practical application and I'd bet on a vet who works in a shooting area being less anti docking.