I see what you are saying, but even players who have not been previously renowned for their defending can still improve that area of their game. Pressing isn't really that effective if only a couple of individuals are doing it, but if the whole team does it, then it makes it far easier even for the likes of Nani and Kagawa to become more effective doing it as part of a structured unit.
SAF simply didn't employ any noticable pressing tactic, so many players were defending on their own and not as a unit. That will especially highlight those players who are not particularly good at that part of the game. Organisation and an understanding that everyone knows what is expected when it comes to closing down, will make even poor defensive players more effective.