Let's look at the example of Leceister. Before promotion in 2014 they were average 22,000 at home. After promotion and before the title win the average attendance was already an extra 10,000 fans and a sell out; almost 50% increase. In the title winning season they of course continued to sell out the ground at 32,000. Does anyone doubt that they could happily sell out 40,000 or more now if they had the means? Many of them foreign I'd bet. Success will bring the fans.