The simple premise is that the priority pick meant Hawthorn was able to get BOTH Buddy and Roughy.It is indeed possible Collingwood don't trade if it is pick 4 instead of pick 7. These sorts of hypothetical things are so hard. But once you undo that trade you massively expand out all these other differences in list management that make the entire process incredibly complicated. I was trying to keep it as simple as possible and only considered the single variable of priority picks existing or not existing.
The entire thing is always just a thought exercise though. Without the priority pick maybe all the clubs draft different players (because of different circumstances) and everything becomes moot.
If no priority pick, they end up with one of them.