Do preseason placements really effect your season placements that much?

Hi, so in preseason I did complete **** and was placed in bronze 1. My friend who just joined the game couldn't do his preseason placements as he wasn't level 30. In season placements, I did well, winning 7/10 games with a 3.15 KDA, good cs, KP and ward score. I was placed in Bronze 3. My friend does his placements as soon as he reaches level 30. Does sort of bad with winning 1/10 games with a 0.55 KDA, nonexistent CS, KP and ward score. He is placed in bronze 1 for this season.

• So I'm wandering, was it the preseason placement of Bronze 1 that messed my season rank up so bad? I can't understand why my friend who is pretty much the type of person you see in wood rank videos could be placed higher than me. It was surprise to both of us.

Any help on this topic would be appreciate, I'm really confused about placements now.