I sort of agree with you, but Push is awesome and totally worth the cost in my opinion.
Even with a Push, there are a couple of WTF omissions that I would have thought would be easy to add, but I assume every DAW will have a few of those.
Lots of people use it Live, mostly negating your argument that the lack of this specific feature makes Ableton unusable live. Actually, is there an alternative DAW that is used live more than Ableton? I would guess the answer to that is "no".