I don't think most of your negative assumptions follow from the points given.

And from my perspective you missed the biggest positive, in that Apple Silicon will have a LOT of custom silicon (Neural Engine, image processors, video processors, etc.) and that should up the performance of certain tassks greatly.

Thre's a YouTube video where someone is editing and color-grading and rendering multiple 4K video streams... on an iPad Pro. And the silly thing isn't even breaking a sweat.