Hummm? Not sure about this, if that were the case, then every ball that hits a defending player, that subsequently crosses the line would be an own goal, because, in your words...
"The Keeper "could" have saved it."
But we know that is not the case, from the god that is Wikipedia....
In
association football, an own goal occurs when a player causes the ball to go into his or her own team's
goal, resulting in a
goal being scored for the opposition.
The fact that the defending player touches the ball last does not automatically mean that the goal is recorded as an own goal. Only if the ball would not have gone past the goal-line but for the defending player would an own goal be credited. Thus a shot which is already "on target" would not be an own goal even if deflected by the defender. In this case the attacker is awarded the goal, even if the shot would have otherwise been easily saved by the
goalkeeper.