Manchester United endured a disastrous 2021/22 season, slumping to a sixth place finish despite holding hopes of a title charge at the beginning of the campaign.

While Manchester City and Liverpool again led the pack and Chelsea finished third, United fell behind once more, with long-term issues with how the club has been run seemingly rearing their ugly head.

Appointing Ralf Rangnick to replace Ole Gunnar Solskjaer on an interim basis did not improve results and the squad's on-pitch performances as hoped. Instead, the only positive from what looks like an increasingly confusing decision is that Rangnick has forced the club into an audit and reset ahead of Erik ten Hag's arrival.

For the Premier League's 'big six', money is no object. That means they can sign who they like, when they like, in order to try and keep their club at the top of the pyramid. However, being able to spend money doesn't guarantee success.

The onus on running a football club efficiently and not putting the brand first is only becoming more and more important, because it's so often done wrong. The age old comeback to United's mismanagement is that they have spent money, so there is nothing to complain about regarding their recent failures.

The same can be said for Chelsea and Tottenham, who have never been afraid to splash the cash to try and reach the top, while Arsenal have also tried desperately to assert themselves once again.

But when we look at how these clubs have performed in recent years, it's clear to see that their spending doesn't align with their subsequent fortunes.

In a bid to represent this difference in how the big six operate, a Reddit user produced a graph using data to highlight each of the clubs' total profit from player sales, starting from the 2015/16 season and concluding with the business conducted in the 2020/21 season.

You can view the chart, produced by user U/LessBrain, below:

Just one glance at the chart confirms one of football's most obvious, open secret; United's footballing operations have been handled abhorrently in recent years.

Having made just £70 million in profit from player sales since 2016, United are by far and away the worst side in the top six for effectively buying and selling players. And it's no surprise.

MANCHESTER, ENGLAND - JANUARY 11: Angel Di Maria of Manchester United during the Barclays Premier League match between Manchester United and Southampton at Old Trafford on January 11, 2015 in Manchester, England. (Photo by Alex Livesey/Getty Images)

They paid a then-record fee of £59.7m to sign Angel Di Maria in 2014, before selling him for a year later for a reported £44m, as United ended the season with a £10m loss of profit from player sales. That's a loss of almost £16m on one player in merely 12 months; one of the best players in Europe at the time, too.

United re-signed Paul Pogba from Juventus in 2016 for a then-world record fee of around £89.3m, but are set to lose him for free once again, which will worsen this graphic if updated at the end of the 22/23 season. We'll have to stop there, because we could go on all day about their poor transfer decisions.

Tottenham have also struggled to make their transfer business prove extremely profitable, accumulating just £185m from their player sales. Signings such as Vincent Janssen, Tanguy Ndombele and Moussa Sissoko immediately spring to mind. Spurs have been far from a disaster in recent seasons, but ultimately have nothing to show for such a narrow profit margin.

While many would've expected Manchester City or Liverpool to top the chart considering how well run they are perceived to be and how much they dominate the Premier League as of now, it is actually Chelsea who have recorded the most profit from player sales, with a huge £462m recouped.

That might come as a surprise to many, considering how much money they put up for players, but Chelsea have always managed to make a helpful handful of key sales whenever making those big signings.

In the summer of 2017/18 where they signed Olivier Giroud, Alvaro Morata and Tiemoue Bakayoko, they also managed to sell Nathan Ake, Diego Costa and Nemanja Matic for equally as impressive fees.

LONDON, ENGLAND - APRIL 22: Nemanja Matic of Chelsea celebrates scoring his sides fourth goal during The Emirates FA Cup Semi-Final between Chelsea and Tottenham Hotspur at Wembley Stadium on April 22, 2017 in London, England. (Photo by Richard Heathcote/Getty Images)

Also consider the sales of Oscar, Thibaut Courtois, Eden Hazard and Morata, it's clear to see that the Blues have been ruthless at the right times, putting them at the top of the player sale profits charts.

But, with new owners at Chelsea, Tottenham rebuilding under Antonio Conte, United and Arsenal doing the same under Ten Hag and Mikel Arteta, and City and Liverpool continually finding new levels, fortunes can and will change quickly in the coming seasons.