...both feature flight models. Why can't this be compared?
No one is saying that you can't compare flight models. But this is how we got here, remember?
FD have set the level when they have released ED Alpha. CIG have delayed their Alpha for 6 months, they had all the information about how ED was received, they have larger team working on project, they knew which level they should have achieved. I do not see viable reasons why AC should not have surpassed ED. But it did not.
Just remember when comparing flight models that you're comparing two WIPs. Although SC is much more WIP at the moment because they're at an earlier stage.