Iuris Tantum ToEEs engine was never adopted in the same way that the infinity engine was, later DnD games used different systems, not that there were many good DnD games after that. and yes you can get the old games, but only if you buy the overpriced enhanced edition that offers nothing that free mods dont offer, besides an expansion that was universally hated.
I get what you're saying now. I was just confused by what you meant by "systems". One of the other reasons for ToEE's engine being largely ignored though was the fact that the industry was moving away from isometric perspectives, in large part because of a collapsing PC market, so the demand for engines ready to do that was very low.
I agree with your overall sentiment though. As I already expressed and elaborated in the other RTwP v. TB thread, RTwP seems to be defended solely by people who don't care much for the combat and would rather get it over with asap. I don't get why they have such strong feelings on the combat system when they can just skip it by playing on lower difficulties.