maybe they dont want to sell him at all and he himself hasn't expressed a desire to move on

Think from their perspective - Osimhen led the club to their first Serie A title since 1990 and led them further in the Champions League than ever before. What's the price tag for that type of club success? Selling him for 100m gets you like 2, maybe 3 solid players but you're still likely short of his goal production.

As an example- Jack Grealish and Villa. They bought Ings, Bailey, and Buendia with the 100mil and none of those 3 have been worth a damn really and Ings was already sold off at a loss. Recruitment is hard and when you have a bonafide star and he's not actively asking to be transferred, put whatever damn price he's actually worth to you on his head versus what all the big clubs want to actually pay. There's zero obligation that you HAVE to sell to bigger clubs.

fwiw though - i saw their new contract they're offering him has a 160mil release clause, not 180