Part of the problem is visibility. Okay, say that I was some sort of high-powered senior manager at Company X. I'm on £100k/year plus bonuses (I wish!). I find out from my old uni mate Virgil, who has a similar role at Company Y, that he's on £200k, albeit without as good a bonus structure. I look at some job adverts and find a few that support this. So in next year's performance review, I tell my boss that I don't think I'm getting paid enough. I'll ask for the £200k that Virgil's on, ignore the bonus structure, but be prepared to take £150k, maybe even less if I like the place. If my boss refuses the pay rise, I've got two pretty obvious choices.
I don't give a damn about the fact that Jan, who's also at Company X and doing a damn fine job for £80k. She's pretty much as good as I am but enjoys being where she is. If she wants to get paid more, she can ask for it. Her body language is brick though.
The thing with football is that everyone knows everyone else's business. It's out there, a badge of honour even. Would you want to work at a company that you feel doesn't value you?
I don't agree with the astronomical sums that footballers are paid. However, the comparison shouldn't be with normal people like you and me, but rather with the superstar stockbrokers, CEOs, etc. They represent the pinnacle of their professions, and of course are lucky that it's a profession where crazy sums of money get thrown around. For the few hundred or so footballers on crazy money -- are there more than 100 of them on £100k+/wk worldwide? -- there are thousands on much more normal wages, and thousands more amateurs at the fat end of the pyramid. Literally, in some cases.
After writing all that, I'm not even sure what my point it. Oh well. That's the internet for you.