The question is, are they better than those we bought?
United first, the rest is just bonus, it's proud to have our own youth going thru the ranks, but first and foremost, they are there on merits, and not just because they're our youth.
I don't think Macheda, and everyone else are better than Chicarito, and if they happens to be, they got time (Welbeck)
I really don't think SAF buying youngster just for the sake of it, he see something we don't, and most of the time he justified his young player signing (ronaldo, chicarito, jones, etc etc) would we fare better if we didn't buy Chicarito and play Macheda instead?
Agreed. (Before I get to my point, I personally think it's time to cut our losses on Macheda. He was worth a try, but clearly isn't quite a United quality player.)
As I see it, those young players purchased fall into two categories:
1: Potential world-class stars who you have to get if you can. Ronaldo, possibly Jones at the time if you listen to the way Fergie spoke about him, potentially Anderson and Nani. I think both Hazard and Lucas were thought of in this category, and the amounts of money that were paid to prevent us getting them seems to support that.
2: Replacements for old players, back-up for weak positions, and basically the players who you hope will be the bulk of the future team. Smalling, Buttner, Powell (may be somewhere between the two groups, hard to say what SAF thinks), the da Silvas, Henriquez, Hernandez etc.
Obviously you have to keep buying the first type. Purchases like that are the difference between CL finalists and PL runners up in modern football. Barca are still on top because even they make them, and Neymar is a great example of that.
As for the second type, although most of those examples were crucial and brilliant at the time, I honestly believe that the huge increase in quality in our academy means we should be making fewer of them now. If Fergie sees that we are weak in, say, central midfield, I'd just like to think that before buying he looks at our reserves. Rather than thinking 'That lad's brilliant but I've never played him in the first team before, he's not ready', he might think 'that lad's brilliant, the coaches say he's one of the best they've ever seen, maybe I should try throwing him in at the deep end.' Personally I think he could have stood to not buy Powell and let Petrucci have a go instead. And if Keane hadn't got injured, the same goes for him and Henriquez (but the injury does make that one more tricky.)
Ultimately, a good academy deserves that sort of trust. But it can't earn that trust until you've gambled on it a couple of times.
(Also I've just realised that in the post you replied to, I named Cleverley. But obviously he's an example of what can happen if you do give a home-grown a chance. I reckon if we'd been Arsenal, his career would have kicked off just as successfully earlier, like it did for Wilshere.)