This is from SwissRamble:
"(d) Spectator mix. Although the “prawn sandwich brigade” is roundly derided by the majority of fans, there’s little doubt that they allow football clubs to get more bang for their buck. Perhaps the best example here is Arsenal, whose move to the Emirates brought them far more premium priced seats and notably expanded corporate hospitality facilities. In fact, Arsenal make 35% of their match day revenue from just 9,000 premium seats at the Emirates. Clearly, you don’t want too many bankers and other corporate types killing the atmosphere at the ground, but an effective balance can be struck."
"(e) New stadium. Arsenal’s move to the Emirates more than doubled their match day revenue in 2006/07 from £44 million to £91 million, moving them four places up the main Money League from ninth to fifth. Sometimes, it is possible to expand the capacity of the current stadium, as Manchester United did in 2006/07, when they completed the upper quadrants at Old Trafford. However, the big money growth, especially for those clubs with smaller grounds, comes with a move to a larger, more modern stadium, which is why so many have been looking at such a possibility. However, as we have seen, there are many hurdles to overcome before successfully completing such a project."
"All of these factors produce vastly different match day revenues per match with Manchester United and Arsenal really coining it at around £3.5 million, while Tottenham and Manchester City earn considerably less at £1.5 million and £1 million respectively. Interestingly, Chelsea generate far more revenue (£2.4 million) than Liverpool (£1.6 million), even though their ground capacity is nearly 4,000 lower. If you ever wanted to understand why clubs are exploring other options, there’s the reason right there."
http://swissramble.blogspot.com/2011/03/is-footballs-gravy-train-slowing-down.html