The Brian Clough comment is a really good one. It's so true that many of the clubs we think of as "big" in some way were really just mid-sized clubs who had one truly great manager who made them far bigger than the sum of their parts. Clough, love him or hate him, was a genius. He did this for TWO clubs, both of whom have achieved squat all since his departure.
In that sense, maybe a truly big club is one that has had at least two truly great managers (or two truly great periods).
If that were the criteria, then we are obviously a big club, having had multiple great periods since the founding of the Football League and two legendary managers. Similarly, Arsenal - who had Herbert Chapman (another genius because he did what Clough did at two clubs when you take Huddersfield into account), George Graham (who was a great manager for the best part of a decade despite his corruption), and Wenger. Huddersfield miss out on our criteria - and I doubt even their fans could argue. Forest, Derby, and Leeds also miss out on this metric, because I don't think anybody could consider Howard Wilkinson's success a sustained period of greatness on any level. It was, effectively, a very happy blip.
Spurs, meanwhile, sort of find their level among the big clubs if we use this criteria. Clearly, they are a big, historical club - but they really have only had one legendary manager. No, Terry Venables doesn't count. They have had only one true period of greatness under Bill Nicholson, though Keith Burkinshaw is underrated.
Chelsea are similar, I think. They had Mourinho's era of domination, but what else was sustained? I don't think Dave Sexton quite joins the greats, a bit like Wilkinson, and Conte and Ancelotti were sacked too soon to dominate.
City have had Guardiola, but who else? Joe Mercer. His record was indeed great, so on this criteria they definitely qualify. But yeah, we're splitting hairs slightly when referencing only managers. It really is about having eras.
Super post again.
Was not aware Chapman had the Clough - two clubs success - about him.
The two periods of sustained success is a great measure. Spurs come up well short on this as do Chelsea and City.
Liverpool, Arsenal, United and us. The Big 4. In ascending level of importance, obviously.