There are plenty of great answers already. But, as to your specific question, I personally could not say as to whether or not a primitive bow can attain perfect tiller. I know there are some dern AMAZING bowyers here on PA...and most if not all of their tiller work looks pretty much perfect to me.
I also know that I certainly have never attained a perfect tiller. I have, however, achieved a tiller that is definitely good enough on a handful of bows. They feel balanced and smooth...balanced and smooth enough, that is. And when I draw these bows in a mirror their tillers look darn good.
But not perfect.
Again, though, good enough. But I know I am not satisfied with good enough myself. Because every time I start a new bow I am striving to make its tiller better than that of my previous bows.