I get that. I'm saying the reason why people say that is because they are considering the opportunity cost and not just the player in a vacuum.
Yes, you get the same player at either price, but at price X there probably wasn't any better player you could have gotten instead, at price Y there is.
Thus, it makes sense to like Maguire at 45 million ( as all the other players you could have gotten at that price were no more likely to be successful), however at 90 million perhaps you could lure a De Ligt or a Koulibally.
It's the opportunity cost that makes him unlikeable at price Y vs price X
We wont buy cheap because a player is cheap
If any player is the right player for us, his cost is immaterial and, if we deem £90m for Maguire is acceptable, then we obviously think he is irrespective of the price tag of others.