You're being too polarized. We want an identity and I personally like bringing in players from the Primavera. But every player has a price, and we need the cash, so you do the math.
If you think Marchisio shouldn't be available for any price, or any player for that matter, then you clearly are delusional.
Delusional and polarized, any other pejoratives you can add to 'aid' your argument? It's not true that every player has a price, there are exceptions, but few and far between in modern football. When a club doesn't want to sell and the player strictly doesn't want to leave then they don't. That's absolutely not the case with the Zidane transfer, which you brought up.
As for Marchisio, he clearly has a price tag because he is not a world class player, but it is also larger than an equivalent talent player would be without his background and homegrown status with the club. That's the same anywhere. I'll repeat, I'd prefer to keep these players and sell others if need be. That also goes for players who have had their heart and soul at the club over the years, adopted Juventini as well as naturals.