Yes that would be what you would do. Of course in practice it's more complex, all eleven plus subs make a contribution to the points total. You want to play and keep the players who make a consistently positive contribution; remove and sell those who make a consistently negative one. The LFC game (at home) he was a clear, positive contributor; the opposite at Anfield, in which he single-handedly lost us a point (probably the clearest possible such case).
All this is aside from my main point, which is that fans on here tend not to take the long view; and are prone to exaggeration (certainly about negative things) and overreaction.
A case in point: Interesting that you are not keen to permit sole factors that earn points -- it's due to everybody -- but quite happy to suggest sole factors exist in the opposite direction.