That is a valid way of putting it.
If Zinchenko was keen on staying, with 2 spaces in the squad and money there, I would think we would still be looking to add Cucurella.
If we had already signed him, before the likelyhood of Zinchenko leaving becoming apparent, I don't think anyone would think, we have too many FBs, we need to get rid of one.
Which then begs the question, why would you not replace an outgoing Zinchenko.
I get BP's and others' thinking though, and I think we have to very much be open minded to that being exactly what the club wants. Time will tell.