That’s just not true at all. Literally one of the most famous games ever made remade with modern graphics couldn’t be successful? When squenix announced a remake, and the internet exploded, that is exactly the game everyone expected it to be. Even at launch day we still thought the story would be mostly unchanged.
I’m not arguing in favor of keeping turn based combat.
How exactly would keeping the original story have made a remake less successful? New players would have played it either way, and I find it very hard to believe that the number of fans of the original who would have avoided the game due it being “the same game” outnumber the number of fans who were sold a remake and didn’t find out until half way through that this was a different game.