And Amauri and Marchisio started in Florence. So what you're saying is Marchisio is a veteran player now? IMO this is just silly stuff here.
This is just silly imo.
Marchisio played +20 matches for Juve and in Florence Sissoko was suspended while Zanetti was injured. He played because we had no other option in CM (unless you'd start with the guy who locked the director in the toilet the very same day).
Amauri was a ~25m eur signing. You can't put him on the bench just like that. Plus, Trez was unavailable on that match.
Giovinco played ~30 minutes for us in his career and his rival for a place in today's match was Pavel Nedved.
You don't put a ballon d'or winner, a Juve legend, on the bench just like that, so some kid (no matter how talented) will take his place. And this kid didn't start a single match for Juve in his life.
I'm sure Giovinco will take Pavel's place one day. But it can't happen over night, without deserving his place.
Giovinco will first have to play 20 minutes. Then 30, then 45 and when he'll prove that his better than Nedved (or Del Piero, Amauri, Trez), he'll play regularly.
That's life and that's how things stand in every aspect of our lives. It's an unwritten rule.