If you're suggesting auto adding everyone who purchased a III to the FC waitlist, then you might have a bunch of folks on there that don't want one. That will hold up the line too.
Or are you saying that when someone who got a III early adds themselves to the waitlist, potentially weeks after someone who has a III and added their name to the FC waitlist first, that they should automatically be moved to the top of the list? That seems unfair.
What about the people that were on the III waitlist, bought it, and then sold it on Reverb for a profit? Do they get priority on the FC waitlist? How could you discern who those people are?
First come, first served is fair. It's easy to manage. There are no questions. It's predictable.