In any case, these "iPad as Screen hacks" still do not address the main issue at hand: Hardware-wise, you simply don't need the (Macbook Air) laptop, at all.
The laptop form is technically obsolete for most users, since Apple Silicone chips are very similar in Air and iPad. The iPad offers more than enough processing power, while having additional capabilities. Breaking this stupid redundancy and better ergonomics are the things Apple won't make for the sake of completely artificial market segmentation. Probably to keep up supply to the golden iOS Appstore prison and consequent double spending on not just hardware, but software, too.
Honestly, every time Apple tries to green-wash their business, you shall remember how they keep the demand for a whole device line up artificially - and its unnecessary production impact on the planet. Dear Apple, who cares about your headquarter's solar panels, or aluminium recycling rate, when you could simply give people a unix shell on the iPad, with a much, much better environmental impact? Yeah...
Side note: Fool me once... the iPad-paperweight experience is the sole reason I would never, never ever even consider getting into their AR/VR ecosystem. Specs my ass, shell or GTFO. Stallman really do be right.