Whilst I get what you are saying, it wasn't the case though, there are quite a few players for each position.
I will grant McLaren the fact that all of his first choice defenders were out, making the keeper descision even more baffling, but had he been any good as a manager he would have had replacements. Due to his bad management, Jamie Carragher has retired from international football, not because of Terry and Ferdinand being in front of him, I'm sure he understands that, but he gets dragged to the other side of europe and ends up being 5th or 6th choice behind rookies with neither the international nor club experience or quite frankly the skill he has. Had he been picked when Terry or Ferdinand weren't fit he'd still have been playing for England and alongside Campbell would have been a much more solid defence, but McLaren messed him about so he quit.
So just that one little thing could well have been the difference, 2 centrebacks with international experience would have been more solid than playing inexperienced players like Lescott, who is not a bad player and will possibly become very good, but he's not an international class centreback yet.
Don't get me wrong, I'd love to see more English players come through and Liverpool have produced a few decent ones in the past, but the last batch were simply not quite good enough and I'd rather see better foreign players at my club than average English players. I'd also like a manager of England that can get the best out of the players he has to choose from, if he can't work with the players he had, then no amount more average players to choose from will fix the problem.
Arfie