Of course, but clubs cant force people to go and/or give their ticket away, hence why I think it's a bit silly to claim "they cant even fill their ground!" aimed at.. whichever club, not just City. Obviously some clubs can't even sell tickets but yeah.
West Ham have, and I quote, "five times as many supporters than available season tickets" on the waiting list for the new Olympic stadium. Whether those people go or not (if they think the atmosphere/stadium is shit after a few months and pack it in) is a different matter, but they still sold all tickets and justified the move (in the short term at least)