Ange Postecoglou and Giovanni van Bronckhorst should leave their diaries free for 2042. All of it.
If Martin O’Neill can fill the Armadillo in Glasgow tonight, 17 years after he managed Celtic for the last time, the market for day trips down memory lane is clearly alive and well.
You used to be only as good as your last game and O’Neill’s was a Scottish Cup Final win – but now you’re good for decades it would appear.
So Ange and Gio will still be box office on the 20th anniversary of one of them winning the league title for Celtic that nobody saw coming. And the other one taking Rangers to a European final at a time when it was thought that level of achievement was beyond the grasp of a Scottish club.
Nostalgia sells. Everything sells where Celtic and Rangers are concerned.
The commercial appetite for the pair of them is insatiable.
The intensity of the rivalry between the two has become immeasurable.
Nir Bitton has been recounting racy tales of being unwilling to leave the house in the immediate aftermath of an Old Firm defeat in case he was ambushed at the shops.
Much to the amusement of his bemused countrymen now he’s safely back among them in Israel.
I met a Celtic fan last week who told me he’d gone online to buy an Eintracht Frankfurt scarf to wear like a comfort blanket when the Europa League Final was on in Seville.
Meanwhile, the Andalucian economy must also have benefitted from the migration of people from Scotland, and elsewhere, for a short, sharp jolly.
Merchandise, season-ticket renewals, it’s bonanza time for Celtic and Rangers as they prepare to spend their Euromillions on turning loan deals into permanent transfers and plunder the market to facilitate next season’s continuation of a title race.
It’s a title race that is their business alone – and by the look of it unlikely to be anybody else’s affair ever again.
Business is certainly booming all right but my attention was drawn to a throwaway line from a teenager last week.
Rory Wilson is 16 years old and a product of Rangers’ Academy – except he has just handed in his notice.
The Scotland Under-17 striker scored against Denmark in Israel during the European finals a few days ago.
Now he wants to move on, move out and go to what he calls the “next level”. Specifically, Rory wants to go to England to become a “top player”.
Earlier this year, after coming on as a teenage sub for Celtic during December’s home win over Rangers, Ben Doak decided he wanted to take that career path as well and eventually signed for Liverpool.
For all that Celtic and Rangers have given their fans a season to remember, wearing their shirt clearly isn’t the pinnacle of life’s achievement for the coming generation who were born here.
And the developmental pathway for kids at both clubs could be booby-trapped tomorrow if Lowland League clubs decide at a meeting to discontinue the idea of allowing Celtic and Rangers Colts to play there in exchange for each club paying £25,000 a year by way of a convenience fee.
Throwing their money around like sailors on shore leave is all very well.
But the Old Firm need to be mindful of how much game time the next generation will get to maintain their progress.
Celtic and Rangers prioritise the domination of one another above all else.
But marginalising homegrown talent in the process is dangerous.
