In the summer of 2019, Premier League spending was the second highest ever (£1.41 billion), La Liga spent more than €1bn for the first time, while Europe's "big five" leagues managed a record €5.5bn between them by the end of the window.
In total, 11 Premier League clubs broke their respective transfer records: Man United spent £85 million on Leicester defender Harry Maguire, and Arsenal paid £72m for Lille's Nicholas Pepe. In Europe, Barcelona lavished €120m on Antoine Griezmann, Atletico Madrid invested that into Joao Felix from Benfica, while Chelsea's Eden Hazard went to Real Madrid for €100m, and Inter Milan stumped up €80m for United's Romelu Lukaku.
After the coronavirus outbreak and economic downturn that has followed, football will have to think differently. Looking ahead in a time of uncertainty, the moral implication comes first.
"It's going to be difficult to justify spending so much money on players when people are ill and dying out there," former Liverpool sporting director Damien Comolli told ESPN.
But once the world returns to some form of normality and the transfer window reopens, football clubs will have to find ways to be creative as the financial crisis hits the sport hard. "I think the next [transfer] window will be very strange," Comolli said. "I think we will see a decrease in transfer fees. We might see players being swapped rather than cash being exchanged. There will be a lot of loans."
At the end of April, Manchester United chief executive Ed Woodward told a fans' forum: "It may not be 'business as usual' for any clubs, including ourselves, in the transfer market this summer... I cannot help feeling that speculation around transfers of individual players for hundreds of millions of pounds this summer seems to ignore the realities that face the sport." Back in March, former Bayern Munich president Uli Hoeness had predicted "transfer fees in excess of €100m will be a thing of the past for the next few years."
Perhaps it's in Woodward's interests to play down the idea of United spending north of €100m on Tottenham striker Harry Kane or Borussia Dortmund forward Jadon Sancho, but it could be that the structure of the transfer market is going to be radically different.
The days of huge transfers between huge clubs look numbered, but as Woodward's tenure has so ably demonstrated, Europe's super clubs have a remarkable ability to conjure money from the ether. As soon as football returns in any meaningful sense, the money -- perhaps not as much, but enough -- will continue to come in. Those big transfer fees are useful to the super clubs, but not integral to their business model, and if they begin to refocus their attention, it will have a big impact lower down the food chain.
"I think the clubs that have got money, and the ones that are clever, could absolutely kill the market in terms of acquiring emerging talent," Comolli said. "A player who was worth £20m in January is maybe going to be worth £8-10m in the summer. Some clubs could stockpile very talented young players for half, or a third, of the market value [they were worth] 12 months ago or six months ago."
That will naturally hurt clubs a step or two down, those "middle class" clubs whose model often relies on selling players they have cultivated to bigger or richer sides for healthy profits.
Last summer, Lille sold nearly €150m worth of players, with Rafael Leao's move to Milan, the sale of Thiago Mendes to Lyon and Pepe's €72m departure to Arsenal making a very tidy summer of business for the Ligue 1 side. But that money doesn't just sit in a giant silo somewhere as a collection of suits count it: Lille used some of it to bring in a series of mid-price talents, a mix of youngsters and gambles that they hope will flourish and then be sold on at a nice markup, just as they did with Pepe, Leao and Mendes. They paid PSG €10m for the 21-year-old Timothy Weah, spent an initial €12m for Nigerian youngster Victor Osimhen and took a punt on Renato Sanches, once the great hope of Portuguese football who lost his way after moving to Bayern.
If the Lilles of this world can't do that, they won't bank those profits on talents they have developed, but they also won't have as much money to sink into the next generation. It's the way that plenty of clubs operate, from Borussia Dortmund at the top end (although they're so big in their own right that their status among these selling clubs is slightly different), through to the likes of Southampton in England, Porto in Portugal and Sevilla in Spain. Moving down a step further, in the English Championship, Brentford have made an art of the purchase of unknown talents for pocket change and selling them on for between £10-20m every year.
Comolli uses the example of another French club, Saint-Etienne, who sold a promising player for big money last summer.
"Arsenal bought William Saliba for £30m, but the next Saliba, by next summer, maybe [will go for] £10m. The French club will still have to sell, because it's a matter of survival." This point was emphasised by Saint-Etienne director Bernard Caiazzo's recent prediction that up to half of France's professional clubs could go under because of this crisis: "That's why it's gonna be an interesting market for people who have got money, who are creative, brave and aggressive."
It's possible that mid-level clubs will continue to sign the same sort of players they always have done -- with promises of playing time their only real leverage -- but it's more likely that the big boys will get who they want as they shift focus away from expensive finished products and more towards emerging talents.
Of course, nobody knows what the transfer market will look like. Nobody knows what football will look like. Nobody knows what the world will look like. The only thing we do know is there will be less money flying around for a few years, and that could significantly alter the structure of football for a long time to come.