It doesn't quite work like that, any new development of the ground would be subject to new terms and could be completely self-funding with the addition of dynamic ticket pricing. In addition, the commercial revenue the club could generate through sponsors and matchday/club shop sales could increase significantly with a larger capacity. The size of a club is generally gauged by the size of it's ground and as long as you manage to fill it, the revenues can increase significantly and it's what we should be aiming to do.
I did say in part its bo**ocks! That said if we accept other contributing factors its still not going to substantially change the overall revenue and change the landscape to the extent that gate receipts and associated match day revenue would ever become say more than 20% of overall revenues for the club, that's 3 times more than present. A significant impact yes, but overall the greatest revenue whilst in The Premier League will ALWAYS be the TV income. I would imagine within the UK and based on current revenues only 4 clubs may be the exception to this, and invariably that's those that qualify for the Champions League and progress within that competition season after season, and enjoy worldwide brand recognition. Aim high by all means but that 'game changing' position for City is many years away at best.