If I could plug my iPad into that cable to use it as a Mac I would do that all the time and buy a more powerful iPad. It would be an iPad for idle browsing and a Mac for the times I need a real computer.
https://www.sotsu.com/products/flipaction-elite-16?variant=4...
Just let me use my own keyboard/mouse when I want to use it like a computer. Better ergonomics too as the iPad would be at a good height.
At that point, an actual laptop is simpler.
It's easy to forget that many laptops are used 99% plugged to a hub and an external monitor. I have a keyboard and mouse I like a lot, and having a tablet floating on an arm next to my other screen instead of half open clam with a useless keyboard pointing at me is incredibly freeing.
Even on the go, bringing a bluetooth (trackpoint II）keyboard is just better overall IMHO. It's up to people's taste, but tablet form factors are not some unsolved mistery. Commercial success would of course be another discussion.