If you look back at our records you will see that we have always had wildly fluctuating attendances. Traditionally, City had a considerable section of support that only turned up for random games. I suspect regular support, as in attending practically every home game has literally never been higher. Over 50k for a League Cup match against Wolves is well-nigh incredible, especially as night matches are an absolute ballache to get to by public transport - or more precisely to get back from. 8-00 p.m. kick offs do not help with this as the transport authorities seem to think that everyone outside the City centre goes to bed about half nine.
I suspect that if the ground was taken up to 70k or 80k capacity, people might be surprised by how often it filled, especially if the prices were right and the hassle of getting a one-off ticket minimised. Several league fixtures are already sold out months in advance.