Let's be entirely honest, also: A perfect "laptop" would be a convertible, or tablet + X. The Air is not missing touch; the iPad is missing a full-access operating system.
IMO, there is nothing a laptop has, a tablet couldn't. Just make it a tiny bit thicker, or add a detachable module for extra battery and ports and storage or whatever.
Why is it better? Most importantly, the ergonomic constraints of a laptop make it totally unfit for a device our lives grow around. It's a legacy, not necessity, now, as we got the power. With a tablet you can have an optional "iMac" setup with a minimalistic stand and free keyboard/touchpad.
Most of the time a laptop doesn't actually sit on a lap, so there is no need to ruin your back over the form factor.
Then there is pen input, which I became insanely dependant on. Hand written notes and little drawings are now essential for helping me to think and work. Visualizing an algorithm to understand it? Yeah like on paper, but add undo, copy/paste and move to it. Sign papers you got sent by mail and send them right back. Screenshot, annotate, process like a human. Imagine poking into e.g. assembly, but being able to draw on the code, highlight, look up... Really, how much "arkane" ASCII habits have we come up with, because we cannot easily fuse digital and AFK note taking? How often have you been _describing something, because you couldn't just draw an arrow right across the text, code, diagram and so on, to reference your note? It's crippling to our mind!
There is no fucking reason to have laptop and tablet as distinct atomic units. The constraints are entirely artificial to sell us both, at this point. If you sometimes need much more processing power, there should be an optional compute module, but really that's not an argument for the Air anyway.
You've been denied an _ergonomic, yet extremely mobile work environment, because people want to sell you both.
There is no other reason.
(Also Linux please)