This summer their president said it wants 400 mil for Osimhen.
I doubt he will leave for less than 150.
400 million? maybe he has lost his mind by setting the price that high or it's just his tactic so that no club will make an offer because he sees this striker as a valuable asset that must be well looked after by the club, but I'm pretty sure no club is willing to buy at that high a price even only for the price of 150 million as you mentioned because his value is not more than 100 million, especially since this season there has been a decline in his performance which of course his appearance will be the benchmark for any club that wants to buy him.
They lost the opportunity to sell him at a high price last season because at that time several clubs were reportedly interested in him, or indeed it was all just rumors.
This is just a tactic so that no other team wants to bid for Osimhen and I think the price of 400 million euros can only be placed on Messi and Ronaldo in their prime. Osimhen is indeed a good striker but not necessarily consistent because this price proves that he is a player who has always been consistent in every season throughout his career, not just one or two seasons. Even the market value of Erling Haaland and Kylian Mbappe only reaches 180 million euros and in terms of quality alone, Osimhen is still far behind these two players.
The owner of Napoli is just exaggerating and I don't think any team wants to sign him (unless Chelsea is in greedy mode). On the other hand, Osimhen will not leave if he feels he is still lacking and maybe he will still continue his career with Napoli despite the rumors.