That's the model that got us there but it's not sustainable at the highest level. If you look at the teams who reach the latter rounds of the Champions League, they take the odd gamble but, mostly, they sign players who are proven at the highest level. Coming from Split, I know the theory: you train quality players, sell them for a lot of money and train even more quality players. Unfortunately, it doesn't work, for various reasons. There's a glass ceiling and you can't reach the top with that model. Potential is an improvement on training players but you need an elite scouting network (one you won't be able to keep for long) if you want your gambles to pay off. Fact is, for eight long years, none of ours did. Of course, it's easy to say in hindsight but it's not about pointing the finger here, just giving my opinion.
It goes without saying that none of the players you mentioned were established when we signed them but they didn't get us a single trophy either. At some point, you need players with a winner's mindset. I believe the club tried to work around that by appointing managers with that mentality but our players were already set in their ways by then. Of course, I could be wrong but I strongly feel that we failed to capitalise on what was an amazing achievement and went about it the wrong way but, again, that's just my two pence.