A few points in response:
1) You are equating her being wrong with him being right. It doesn’t work that way.
2) Not being cruel and vindictive is very much a Torah value, not merely a modern fabrication.
3) ???? ????? are the precise words I heard from a dayan regarding a case where al pi din he is not obligated to divorce her, but he should for Gan Eden purposes. I am not knowledgeable enough to go through all of the relevant halachos with you; as I said, it’s a guess.
4) Yes, I think he can withold for custody issues, but for Gan Eden purposes the arrangement should be based in the children’s best interest, not his or even “justice’s” best interest.
5) There is no question that there are cases where the marriage is unsalvagable. I think this should be determined by an objective party, according to Torah values rather than modern values, and when it is determined, and all other matters are reasonably settled, he should, and should be encouraged to, give the get.
6) Although I’m no expert, from the little I’ve read, you misunderstand the purpose of the cherem d’Rabeinu Gershom regarding a forced get. It is not so that she can prolong the marriage indefinitely; it’s to prevent him from easily divorcing her at whim. In no way, shape or form does this indicate that there isn’t a point in time at which it’s clear that she should accept the get.