I think it would have been great if Young had been forced to start all of last year.

Trouble is, he really wasn't ready. Black hole on D, at best mediocre offensively, no strength and still not fully recovered from injury.
There is no way to precisely calculate this, but IMO giving him 10 mpg would have cost us something around 10 wins, ie miss the playoffs, which is too high a price to develop a talent.
No, but neither were Wiggins or LaVine at the start of the year, either. Like I said, it took a significant portion of time for both of them to get going, but as they're a part of Minnesota's future, it's in the best nature of the franchise to play them.
In regards to your last point, I respectfully disagree. If Young was given 10 minutes a night and that did cost us about 10 games, and thus, the playoffs, that's awesome, imo. I would have rather missed the postseason and come away with Winslow for our trouble at 10 instead of making the playoffs and getting swept, which left us with the 16th pick. That way, at least Young gets some time, and we significantly upgrade our talent moving forward. Wouldn't you rather have a core of Winslow, Smart, Young, and the rest of our young guys moving forward than our current abundance of roll players? That's how you build a team, to me - year by year, piece by piece (or pieces), and that isn't even counting the other 3 draft spots. Coming out of one draft with Winslow, Hunter, the other 2 second rounders (whoever they would be, as I disagreed with who should have been taken at 33 and 45, respectively. Shocking, I know (sarcasm)

), and any assortment of undrafted guys would have given us an absolute goldmine of talent, imo.