Cause we don't throw 30 Million down the toilet.
If we can get Rossi for 25M I'd say fly him to Turin right away, and if we did pay the full 30M I still wouldn't think its money down the drain.
However lets think for a moment if we don't Aguero, Rossi, Benz, etc. which is highly probably we'll be looking at something like this:
Buffon
Licht - Bonucci - Chiellini - Ziegler
Krasic - Vidal - Pirlo - Marchisio
Matri - Quag
Which is quite underwhelming.