I'm higher on Jalen than most but I don't see that at all, tbh. Siakam has elite fluidity for his size, while fluidity is one of Jalen's biggest issues. Bosh was a top prospect in high school, super polished as an 18-year-old freshman in college, had elite touch from day one and had a body that allowed him to be a post-up threat.
IMO, Jalen at his best will be a third option on offense who relies on others to create for him. It looks like he'll be useful in the right system but I don't see any star qualities like were apparent with Bosh on Day 1.