Don't blame AC because you can't fly from YVR into LGA non-stop. It is the US rules that limit the distance from which flights into LGA can operate, and what slots are available into the other NYC airports. Or that you must meet an elderly relative at LGA. That's your issue, not theirs. As for half-miles on domestic, remember that for elite status qualification, many US carriers now count discounted economy as only 50%, so AC isn't the only culprit here. Why should you get full miles when you pay between 10% or 20% of the full economy fare? This happened even when there was competition in Canada. That it doesn't happen on transborder flights is due to the current situation among US carriers, and AC matches that competition.