Speaking to ESPN FC, De Laurentiis remarked upon the premium prices paid for players by Premier League clubs, suggesting Koulibaly would cost a top English side £250 million if valued in line with Maguire:
"He has a clause of £150m. But, for example, in England, they paid £85 million for a player. In Napoli, I would pay £30-£35 million. With that in mind, I think Koulibaly's value is £250 million if they paid that much for that guy.
"The problem of the super cost of the players is due to England. In England, they gross more money than in France, Spain, Italy and Germany.
"If a club grosses £800 million, they have no problem to offer around £80 million, £90 million, £100 million for one player. There is not a real good and fair competition between England and the other countries."
Leicester stood firm in their opinion that Maguire, 26, was worth a new world-record transfer fee if he was to leave the King Power Stadium. They eventually secured a figure surpassing the £75 million Liverpool paid to sign Virgil van Dijk from Southampton in January 2018.
Though unlikely, The Athletic's Liam Twomey had previously suggested Leciester reinvesting their money in Koulibaly:
The Senegal international has regularly been linked with Europe's powerhouses—particularly those from England's top flight—for several years now.
It's not the first time De Laurentiis has used hyperbole to ward off interest in his defensive gem. Koulibaly, 28, joined Napoli from Genk in 2014 and has cultivated a reputation as one of the best centre-backs in Europe, leading his club to successive second-place finishes in Serie A the past two seasons.
Many might agree Koulibaly is a superior defender at present—though perhaps not three times the defender—but age is at least one advantage Maguire holds over his Napoli counterpart.
Paul Hirst of The Times detailed why United manager Ole Gunnar Solskjaer was so determined to secure Maguire as his centre-back upgrade this summer.
Maguire has signed a six-year contract at Old Trafford—with the option of an extra year—and football writer Sam Pilger detailed Solskjaer's logic in pursuing the England international:
Many might not agree Maguire deserves a higher transfer fee than 2019 Ballon d'Or contender Van Dijk—perhaps rightly so given the Dutchman's instant impact delivering success to Liverpool.
However, De Laurentiis' valuation of around £35 million for Maguire also looks slightly insulting.
Statman Dave hailed Koulibaly's elite numbers and goal-saving contributions during an encounter against Inter Milan in May:
De Laurentiis will be glad to see another Premier League transfer window deadline pass with Koulibaly still part of Napoli's squad. Serie A's transfer window doesn't close until August 23, but the chances of him leaving are much slimmer now that a move to England is off the table.
Maguire could make his United debut at home against Chelsea on Sunday when the Red Devils begin their 2019-20 campaign.