The whole 'Old Firm' thing originates back in 1904 when the feeling was that Celtic and Rangers used to engineer additional games against each other as a way of drumming up extra revenue. They enjoyed a good relationship back then, their enduring religion-related enmity really only starting to take hold a decade or so later in the years just before and during the first world war.
Their games are the biggest draw in Scottish football by a country mile, but it is difficult to see how they could be all that compelling if the gap between the two sides continues to widen.
It is 50 years now since Celtic were champions of Europe, but they were just three points better that season than Rangers who also reached a European final. These days, Celtic are ranked 46th by Uefa but looked a world apart from their Glasgow rivals in Sunday’s 2-0 Scottish Cup semi-final victory.
When Scott Brown said afterwards that he and he and his teammates knew that if they “turned up” they would win it didn’t even come across as a jibe. Rangers are back in the Scottish top flight and Celtic are feeling the positive effect with the renewal of their old rivalry contributing to substantially increased interest and attendances, but the blue side of Glasgow is a shadow of the club that went bust five years ago and nowhere near what they need to be in order to make Scottish football even remotely interesting again.
Inevitably, money is at the root cause of the problem. Celtic spend twice on player wages what Rangers do, although the numbers are modest by comparison to clubs south of the border in England.
The average annual salary at Parkhead is just short of €850,000 according to a Sporting Intelligence report released last November. That compares to just €375,000 at Rangers where, one presumes, Mark Warburton ultimately lost his job (you can argue over whether he technically resigned or was sacked in the end), less for failing to keep pace with the club's old enemy, who are now 33 points clear of them in the table, and more for having allowed his side to be overtaken by Aberdeen where the corresponding salary figure is just €160,000.
It would be tempting to suggest that almost anybody could do what Brendan Rodgers has in the circumstances, Yet it is worth remembering that while Celtic have generally dominated in recent meetings with their rivals, Ronny Deila announced that he would be departing after his side lost on penalties to the same opponents at the same stage of the cup last year.
Rodgers has, in fact, done well, and Rangers are reduced this coming weekend, when the two meet again, to trying to prevent the champions getting through the league campaign unbeaten; something that would, for all the financial disparity, have seemed a little far-fetched in the days after the Scots managed to lose 1-0 away to Lincoln Red Imps of Gibraltar in the qualifying stages of the Champions League.
There, of course, the numbers were ultimately turned on their head. Celtic’s wage bill might be big by Scottish Premiership standards but with it is less than a third of the Premier League’s average spend and a couple of hundred grand short of the English top flight’s poorest paying side, Burnley. So it was hardly a surprise that they struggled to make an impact on a group that included Barcelona and Manchester City.
However, their three draws, including two against Pep Guardiola’s side, represented a decent achievement and the home game against City yielded a pretty memorable night.
The money earned for making that stage of the competition will help widen the gap at home but it will do little to get Celtic to where Rodgers would like them to be, the sort of level that so many of the club’s fans feel befits their big club status.
As things stand, all of that looks to be permanently in their past. Rodgers talked on Monday about wanting to sign two significant players in order to make the team more competitive in Europe next season but over time he will be vulnerable to losing players to clubs that will pay them far more and allow them to compete, week in week out, at a far higher level. If he defies the odds and continues to make progress against serious overseas opposition regardless then Celtic will be vulnerable to losing him in precisely the same way.
There is, in any case, something a little less special about the Celtic of today because of the way the game, and the world it is played in, has changed around the club. The religious loyalty is, for a start, increasingly an irrelevance.
More obviously, though, the increased movement of players has changed the team’s character. If that great team of 1967, the Lisbon Lions, can be celebrated for the fact that only one was born more than 10 miles from Celtic Park then it is tricky to see how a little of the magic is not missing from the current side which included only one truly local lad, Callum McGregor, at kick-off on Sunday plus a couple more who have, at least, lengthy associations with the club.
The club still runs a decent youth development system but more than half of its current first team were born outside of Scotland, even if Kieran Tierney did move to the club's catchment area at an early age from the Isle of Man.
The point, in any case, is that few of the better ones will forge anything like the bond to the club that their predecessors did with eight of Jock Stein's starting line-up against Inter Milan spending a decade or more of their careers in green and white hoops and the likes of Billy McNeill, John Clark and Bobby Lennox scarcely kicking a ball in meaningful competition for anyone else.
If he fulfils his promise, on the other hand, Moussa Dembele is likely to be fondly remembered for a couple of great seasons and as a great buy sold on for a big profit.
Quite how Celtic can break out of their current position without huge spending, in turn creating a dramatically different competitive landscape is almost impossible to see. In the meantime, their fans might be willing to wait until at least they win a 10th successive title but they really could do with Rangers being good again.
