Big teams have players that are under utilized, but it does mean when you have long list of injuries you're covered with quality.
There are teams that can basically afford to do whatever in the transfer market without it having any long term implications. Real Madrid are an example of that. They can buy in a few young players, play them, not play them, it doesn't matter. They can just write it off as a loss at some point and it's all good.
Clubs that have to live more within their means and / or have a bit of a more thought through strategy try and achieve a good balance in the squad. If you want squad players then you need to make sure they have reached the right point of maturity to be able to dip in and out of the team and maintain a good level. Are young players that are still learning and developing the best candidates for that?
Take Coates as an example. We bought him at a relative premium of 7.5M given that he was approaching at the peak of his breakthrough period. And then what? He was used a squad player. Under-utilized. Would you say we've gotten 7.5M worth of value out of him? What would you say his value is now? Not very much.
Danny Wilson was exactly the same. We bought him for 5M on the back of starting to establish himself for Rangers and did nothing with him. We ended up giving him away.
We can't afford to be taking those kind of hits regularly - especially if the initial fee is in the 10-20M range.
Now the players being mentioned in this thread might be better than those two but the fact remains that they still need games to develop. Suggesting that it's the managers problem to figure it out is just ignoring it. You're setting him up to fail (hence the Daniel Levy reference).
Let's take another example. Would Henderson be the player he is today if we paid 16M for him and then just had him come in every 5 games? No. Would he have been able to come in and be of the quality needed without that time to become quality? No.
Will the likes of Can be the best they can be if they get that sort of treatment? The answer is probably the same.
You want to pay a premium for top young talent? That's fine. Make sure they are going to get the time and games they need. You want someone that will pad out the squad and do a good job when he's called upon. That might require a different player profile.