>>17198078do you think it might also have to do with proportions? Cain gave him some wheat maybe like 1/1000 of his harvest. Abel gave a firstling of his flock probly more like 1/20 of his harvest. Abel gave a much greater sacrifice according to his means.
I could see the other interpretation too, of preferring animal husbandry over grain farming and what you have said makes some sense too.
They mention fat in Abel's sacrifice too, which seems to be the favourite sacrifice throughout the Old Testament.