It’s a really difficult design challenge. I want a solid laptop experience, a quick and easy conversion to an inclined writing surface, and a lightweight detached tablet mode. There still isn’t a single system that does all of that.
X1 Yoga: not super light (3lbs or so), and switching from laptop to ‘tablet’ is a big move (flip the whole thing inside out) meaning you might have to disconnect from a dock, and it’s clumsy on the plane. The tablet mode is also not inclined by default, you have to prop it up by hand. And of course: no detached tablet option.
Surface Book: going from laptop to docked tablet required a slowish disconnect reconnect. The disconnected tablet was unwieldy because of the lack of a kickstand. Battery life was also very short (~1.5h) to keep the screen portion thin and light.
Surface Laptop Studio: very easy to switch from laptop to slightly inclined tablet, but it’s heavy (3.8lbs or so) and no separate tablet mode possible. It also has quite a bit of flex during writing because of the very thin screen.
Surface Pro: closest, but no solid laptop mode. Divine tablet mode (perfect kickstand) and decent ‘floppy laptop mode’, but incomparable to the solid laptop mode of e.g. the SLS.
As @jhoff80 mentioned, the device that does it all would have a (battery filled ~2lbs) base and a docked Surface Pro as the screen portion. It would be an odd duck though, having both a laptop hinge and a kickstand. I think it would be an easy system to make fun of. Still, it gets close to having everything in a single system, at ~3.8lbs.
The other approach that could get close is something like the 11" iPad on a magic keyboard that could fold nearly flat, as seen in an Apple patent application. Downside: still no kickstand in tablet-only mode, but a potentially convenient switch from laptop mode to inclined tablet mode. I honestly think this would get the closest to a realistic solution, but of course just to annoy us, Apple will only offer it with iPadOS. 
So overall: not a problem with an easy answer! I guess all we can do is Wait-and-hope™.