They've already achieved that though, that could be done today, HT's used muscle bodies, while the sculpts could use some improvement, with today's paint jobs and the right sculpts, they could look very lifelike, but they'd lack posability. Ultimately, you can't have joints hidden, fully articulation, and have the body always look real in any pose, you either have to make the skin thin and you end up with weird folds that you dont' get in the human body, or the skin is so thick, you can't pose things.
The new bodies are really the best option for a collectible figure, it looks more realistic than a standard base body, but it has most of the posability such a body would have.
Some people may care more to have figures look as nice and realistic as possible, but I think for the majority, the allure of figures is the posability, and we just luck out that we also get such a nice aesthetic. There are statues out there for people who care more about seemless bodies and all. I don't see the figure market ever being comprised of a majority that would sacrifice function for appearance.