I think Siakam can be the Draymond on a championship team as he proved in 2019 (3rd option, defensive star, etc) but the issue is the Raptors maxed him out and he's not a player that you build around. So if the Raptors keep him and he's their #1 option, then they will be a ceiling in terms of how far they can go. One of the reasons Masai is a great executive is because he always thinks big. He didn't value being in a play-in game because it ultimately meant nothing. If he sees a limit to a Siakam lead team, then trading him for younger pieces and a shorter contract makes sense.
Maybe something like Wiseman, Wiggins, #7, and #14 for Siakam, #46, and #47. Squeezing an extra 1st would be nice.