I agree with most of your points in this thread. But I'd say iPad software is mostly limited by Apple's rules and policies. Since iPadOS is essentially a re-skin of macOS they could allow Terminals, virtual machines, file system access, emulators, Homebrew, background tasks, but they don't want to.The capabilities of most iPad software is limited not by the OS but by the design choices of the designers and engineers who build the app.
Looking at touch input on the iPad, the god awful text selection makes me run to my Mac every time I need to do like anything with text. Some people might say get the keyboard with trackpad for your iPad Pro. But if what I need is more like a Mac I'll choose a Mac with better window managament etc.
For me the new iPad Pro is as much of a content consumption and gaming device, a non-essential toy, as the old one was. I do not see how the faster chip and better display suddenly make it more "Pro" than the M1 or M2 generations were, not for me, and not for creative professionals.
Because I'm fully aware that some people can use an iPad Pro for their profession, for them it has a much different role than for me and my compilers and virtual machines and stuff. I don't believe these people, happy with their M1 and M2 iPad Pros would agree to the M4 iPad Pro "finally" being Pro.