I don't know about the numbers because I can't be bothered to work them out but the logic is sound. It's not really a suprise that the average caftard fails to grasp a mildly complex idea though.
Theoretically Arsenal have RVP for 1 more year, on relatively low wages for one of the top 5 strikers in the world. That's not a total disasterous position for Arsenal, even if he leaves for nothing next year. If he signs a new deal then they are shipping an extra £50000 (or whatever the rise is) per week + the signing on fee.
Alternatively (and the more likely scenario) they can cash in on their player. But what is his contract (1 more year on low wages) worth to Arsenal, 8,12,15,20,25 million?
This of course ignores RVP's apparant desire to get out quick - which could affect Arsenal if he was to stay.
Similarily with Modric last season - Spurs have the player with a long term contract on a relative pittance. Even in the face of a huge transfer fee, Spurs had a good incentive to keep the player because they already had him on a favourable deal. Redcafe said he was gone but ended up paying Glaston's electricity bill.