We know God is strong enough to make his desires come to pass. We know it is his will that all be saved. So there has to be an explanation as to why some wont be saved....And that is because they choose not to accept the free gift that has come upon all men.
Romans 5:18
Therefore as by the offence of one judgment came upon all men to condemnation; even so by the righteousness of one the free gift came upon all men unto justification of life.
ALL means ALL...just saying
Your first 3 sentences I TOTALLY agreed with.
Your 4th sentence, your conclusion, I don't agree with.
There is nothing special that resides in those who will be saved vs those who won't be saved that causes them to make GREAT decisions.
It is merely the Lords Leading that causes those who will be saved to make those GREAT decisions.
I would like to focus on your sentence
"So there has to be an explanation as to why some wont be saved".
Romans 9:21-23
21 Hath not the potter power over the clay, of the same lump to make one vessel unto honour, and another unto dishonour?
22 What if God, willing to shew his wrath, and to make his power known, endured with much longsuffering the vessels of wrath fitted to destruction:
23 And that he might make known the riches of his glory on the vessels of mercy, which he had afore prepared unto glory,