Idk much abt his off ball movement but his shooting and passing has looked pretty good to me?

Kinda is. All 3 of Siakam’s older brothers already had played college basketball and were recruited to go overseas by the time Siakam supposedly first started playing basketball when he was 16.

In other words, this story that Siakam only picked up a basketball when he was 16 isn’t even true unless he never interacted with his brothers at all growing up, all of whom played D1 basketball. In reality, it’s just saying Siakam only took basketball seriously at age 16. Same goes with Yaxel. He had parents who played basketball but he also just never took it seriously until he was older. It’s not literally the age when he first picked up a basketball since he clearly played it earlier. 

I do agree with your general statement that he is kinda lucky to go as high as he did. If he had a different backstory and also had played earlier, he gets chosen in the 20s like Zuby Ejofor or Alex Karaban, two other older players. However the backstory matters a lot. It gives him this weird ceiling that players like Pascal Siakam, Mark Eaton, or Dennis Rodman reached in the sense their age adjusted production is closer to that of a younger player. It’s also why Chris Duarte was chosen so high since he was a later bloomer too, although he was a bust so it’s not always just good players.