While United and other English clubs were setting domestic records in transfer fees during the early-to-mid 90s, Italian clubs were setting world records with fees 2-4x higher. Lentini and Baggio come to mind.
As for Robbo and the fee then comparative to today, what was Robbo's wage in 1981? I figure probably something like 50k per year. I know US athletes didn't start earning in the six figures, on average, until the 80s. By the 90s they were averaging in the millions.
That's just it - US sports people earned so much more in the past largely because their sports had a larger fanbase, the US has a fair amount more people than the UK does! I remember even 15 years ago in Ireland it wasn't as easy to follow United. Most games weren't on TV, oftentimes the only options were a fuzzy BBC Radio 5 reception on longwave, or checking teletext literally every 2 minutes!
These days I can watch almost all United games from pretty much anywhere in the world with an internet connection, and can keep as up to date on the latest club news as someone living within a mile of Old Trafford - having a worldwide audience instead of just a largely UK or English based support means a hell of a lot more money, and I don't think that's ever likely to go away now, as long as the game remains popular. Unfortunately, as has already been pointed out, many clubs are yet to adapt to this change in football, and many are falling foul of this.
Whether footballers deserve their gigantic wages is admittedly debatable, but I firmly believe they deserve it more than most anyone else involved in the game. If there's that much money in the game it's got to go somewhere, and who else deserves it more? Becoming a footballer is not without effort, risk and drawbacks. Upon retiring I'm sure many top footballers find they don't have a whole lot to offer the world, seeing as they spent most of their lives working hard to become good at something which they can no longer do, and in most cases that's before they've even hit 40!
As I said, I don't begrudge players the money they earn from the game - basically speaking it's big business now, not just sport. What I wouldn't mind seeing is player salaries spread out over their lifetimes rather than the length of their careers. Say Rooney earns £100k per week right now - his take home earnings every week are capped at say 20% of the total, with the remaining money paid into a fund which is paid out to him weekly after he retires, as a pension of sorts. I think it could only be a good thing for the game and for the players alike.
