Soldato
Your point being what, exactly? You've started your post with "but that's not the point" and then gone on to reiterate a position that precisely nobody disagrees with.
You stated that they aren't the entire workforce, as if that somehow means it doesn't matter if they're crap at their job or staff retention is poor.
The problem is that if a warehouse picker screws up, a customer might get some extra items or be missing something from an order, if the accountant screws up then maybe the company can't afford to pay everyone their £30k salary, or they get fined for discrepancies in their taxes.
Staff retention is an issue because every time someone new starts, a) they take a while to get to full efficiency and b) someone else has to stop working to train them