A good many things would need to go our way for that to ever happen again.
When we play City now, I write off that game as a loss. We've been crap for donkeys, but I always had an inner belief we could be competitive on that day and nick a draw (and that's away, even possibly sneak a win at home).
Be that SAF's United, Wegner's Arsenal, even Mourinho's Chelsea. Although I don't remember that actually happening with the latter, however we still had some games we (nearly) gave as good as we got.
We are further away than we have ever been before, basically we get bummed every time we play City and to get a result they need to put in a massively sub-par performance in regard to finishing and miss most if not all of their 20 shots on goal. If we can't lay a glove on these teams now and year after year they earn 3 or 4 times more than us, that gap is just going to get bigger. We are just like a team from a lower division to these guys.
We have to hope the new stadium closes some of that up, perhaps prompting a better class of owner to come in at a point the rules aren't so prohibitive to be able to spend. More likely we need a revolution to even the field, where a salary cap comes in to play.