I must preface my remarks here by stressing that these thoughts are mine and mine alone. They are not indicative of the teachings of the religion to which I belong, nor of any group of which I am aware.
Many people have a struggle when it comes to thinking of God as a caring, loving god and at the same time must reconcile that with the concept of, at a minimum, denial of eternal life to sinners, and, at worse, an eternal life of torture for sinners.
I proffer for your consideration, the thought of a situation where ALL are saved into an eternal life in heaven. I submit the idea that God, as a loving god, refuses to deny heaven to anyone, no matter their sins while on earth.
If God's intention is to demonstrate to the rest of the universe that sin is bad, He could accomplish that by allowing things to develop on Earth, as they have, with conditions growing worse and worse. This would seem to make it manifestly clear as to the effects of sin. Then, if He were to save all, even those sinners whose names have become synonyms for evil, would that not demonstrate His loving nature? To put it simply, thus killing two birds with one stone?
Does this seem unfair? Why would it be more unfair than eternal suffering merely because of one small sin? Obviously, if this were to be the actual truth, it would not do to have this concept widely spread because then there would be no motivation for even trying to be good, so that might explain why the Bible does not indicate anything definite along this line.
This idea is, I know, heretical to the vast majority of religious people, but to me, your normal sinner type person, it brings food for thought which I find personally comforting.