Why aren't people's normal mmr taken in account for placements?(slightly salty)

I tend to disagree with people that blame a game on a single person because everyone makes mistakes in games from level 1 to rank 1 challenger but in my last game i had a person playing in a silver 2-gold 4 game in their first placement and they were completely out of their element. One could just tell by how that person played the game and everything that this person is obviously a beginner and should be playing other people of similar skill either in low bronze or not in ranked in general. But he ends up playing in my game and gets utterly stomped but its not even his fault. I go back to look at his stats to find out that it was his first game in ranked ever and looking at his normals history its quite obvious that he still hasnt even figured out the basics of the game along with him having around a 40% winrate in normals. I just think that possibly placements should take into account normal mmr/winrate before tossing someone into a game of much more experienced players its not fair to the teammates that get dragged down and its also not fair to the player because being utterly outclassed like he was couldn't be fun for anybody and also reading most of your team flaming you is also not the greatest feeling in the world either i'd bet.