This is only in an economical sense of the sacrifice of Christ. It does not make the sacrifice of Christ ineffective in reality. If I flip a switch in my house, the light comes on. If I don't flip the switch, is the electricity ineffective? Or just not activated? Analogical arguments always have weaknesses and this one is no different, but it points at the meat of the weakness of your argument. Namely, the lack of response on the part of the sinner to the sacrifice of Christ in no way lessens the efficaciousness (that's probably not a word, but you know what I mean) of the sacrifice.
If man can acquire his own salvation, then God's mercy is limited to what man allows God to show him.
This is a nice painting with broad brush of Arminianism, but does not reflect well the overall idea. Acceptance of a gift given is acquisition. But it is not acquisition by work. It is acquisition by acquiescence. And if you think accepting a gift is work, I'd hate to see you on a Saturday work day at the church.
So you make all your decisions with your eyes closed and a bag over your head?
Your view of salvation relies on its acquisition by man's choice and not God's. It is acquisition by man weighing the merits of his options, assessing whether or not to accept God's "offer" of salvation.
It is acquisition by man's intuitive faculties, his higher judgment, his profound piety, his well-stocked library, his superior discretion, his smarter hunch. Nor the number of indulgences he can afford.
All this wrestling with the decision to "accept" God's "offer" cleverly leaves the ultimate fate of mankind's soul up to man and his well-reasoned choice, and not to God and His eternal decree.
But I think God demands the final answer on just about everything, whether we want to give it to Him or not.
It is all of Him, and none of us. That's why it's called "Irresistible Grace" by those who know their sorry brains and puny decisions have nothing to do with it.
That's why it's a "gift," unmerited and nonrefundable.
Another good one. And "efficacy" is the form you are looking for.
SD