"Leeches" also known as...poor. Napoli have the wage budget of Burnley, and they're competing in the CL and against Juventus who as well as a much larger wage bill also have double their revenue.
Getting Champions League revenue and good money for players they've invested is how they survive, and asking €60, getting €50-55m for players like Jorginho is the only way they manage to compete, and in a market where Fred and Fabinho are going for the same amount, it's a more than fair price.
They can't afford to pay much for players we sell them because most of the time they're breaking their wage structure just to convince the player to sell - not to mention we're usually selling them 30 year olds with no resale value for them.
See
@jrb's post above for more evidence of their being poor.