WHy should it? There is no reason an its a limitation in how AEs current hardware acceleration works. You have to accept it and wait for a future version to perhaps take advantage of it.
Why shouldn't it. When I upgraded to this new Mac Pro late 2013 with its dual video cards. Premier turned into a blasting fast editor. I no longer need to render my edited cuts and the scrubbing of preview and timeline footage is phenomenal. The only performance boost I've seen in AE with this new system is in rendering and I can't even say its double as fast in comparison to Premier or Encoder and its an 8-Core system with 32GB of ram. Everything else is flying.
So again to answer your why should it. I rebuttal with "Why shouldn't it". The other two mentioned programs are using GPU resources to improve performance why is AE so behind the curve.
I'm not the only one asking why. I was in the audience at a Dmala meeting here in LA with Todd Kopriva and Al Mooney previewing AE and Premier 2014.
People kept asking Todd about performance boost in between questions about new features. Todd finally just asked what do you prefer a couple of new features or performance boost. Everyone wanted performance boost over new features. If you think I'm making this up go ask Todd Kopriva.
Here's the deal for right now: AE doesn't use that memory on the video cards. Period. You can crab about it all you want, but you're not going to change that RIGHT NOW. So just deal with it.... and in your case, grumble. And submit feature requests out the wazoo.
The forums are here to post concerns and to have a discussions. Your ton is condescending and disrespectful in promoting such endeavors by bullying this discussion to a halt.
I know this issue is not getting fixed today nor next release. If you review my statements in more detail you will note that I never stated a need for this to be fixed immediately.
That grumbling and "crab" you so elegantly stated is me asking a simple "why". That is the point of these forums to ask why and to discuss. Mylenium stated his opinion and I stated mine you can consider that a discussion and that's the deal for right now.
So unless I broke some forum rule about discussing concerns on a products performance for which I like many others are paying a subscription for. I will respectfully continue "grumbling" and "crabbing".