If the ADQ is about profitability then the half requirement for non residents does not make sense.
Cow for example would seem to spend less and yet would seem to use "benefits" such as concierge etc than others spending more.
I understand what some are saying about why it may seem fair to give non residents a break but it does not align with the profitability angle.
As for enticing US fliers away from others I would say that AC changes has done the opposite. More and more seem to have given up on AC metal or using AC.com when flying into the US and instead just focus on US carriers.
In the past would have tried to choose AC metal or use AC.com even if slightly higher price, but instead now there is no incentive ever.