Exactly and if they are going to cherry pick a couple of seasons in the mid 90s(Newcastle) or early 00s(Leeds) where they both spent beyond their means and ended up struggling financially for years after. They'd be fooling themselves because City would be no different in the same positions, the attendance data shows it.
Neither club had to compete with a club as big as United next door, in fact they were both pretty much the main attraction in their entire regions geographically.
In the North West, there is the two biggest English clubs just for starters(could have been case closed). But then there is Everton of course... And back then(90s-early 00s) Blackburn, Bolton were probably both still bigger than Middlesborough and either Sheffield clubs were too. That just leaves Sunderland for Newcastle, who weren't anywhere near challenging. Unless I'm forgetting someone?
How quickly did some Newcastle fans and Leeds fans develop the rag like mentality btw? Considering how briefly they challenged and neither of them won anything at all(not even the smaller cups) if I remember right. City have dominated, are actually way bigger than both globally these days and they still don't go around belittling other traditional topflight clubs. Mad really.
PS/Open question for the data nerds: I know Newcastle outspent United when they challenged but did Leeds? I know it doesn't technically matter for my argument because we know it was money they didn't have by what happened after. I was just wondering, I might check myself when I have the energy for it.