I'll just say that both obsidian and owlbear, the companies with much less resources, managed to pull it off quite well, so it's possible if Larian wanted to do it. I don't think they do though and and it's not such a big deal.
Yes, the resources argument is B.S. It is purely a matter of whether they want to do or not.
I'll also add that out of these three companies, Owlbear did it best. I couldn't believe I can just turn it on and off it's amazing. I found that RTwP works best with mobs but I really enjoy turn base in boss fights