Not defending the OP's thesis but clarifying my tl;dr summary of it: Fetching instructions is not the main problem, it's the data that the instructions have to

Not defending the OP's thesis but clarifying my tl;dr summary of it: Fetching instructions is not the main problem, it's the data that the instructions have to act upon (Hence the exception for the compute heavy, data-light applications.) And since most of the compute power in the world today is basically processing and moving massive amounts of data around, I can see how that thesis would make sense in the general case.