Nice thread. There's a common quote in photography, that I'm sure many have heard: "The best camera is the one that's with you."
I still own (and use) a 2017 rMB, and that's how I feel about it. I've got a Mac mini setup for my main, desktop work, but use my rMB for couch and travel. I guess it's my iPad-alternative (and no, I'm not interested in an iPad, I'm surprised this thread hasn't got hijacked by iPad campaigners yet, which is usually what happens on rMB posts

.)
Sure, an M1 MacBook Air is way faster, more ports, etc; but, I know that I won't reach for it on the couch, and will be reluctant to take it on trips (and if I did, I wouldn't enjoy it as much). I think, perhaps because it's an ageing machine that many consider to be flawed, threads like this make non-rMB users think that we're in need of "enlightenment". Along with the iPad suggestions, there's always people graciously helping us out with physics , by letting us know that "The Air is only X heavier".
Yes, we're okay with math thanks. The rMB IS 0.92kg and the M1 MBA is 1.29kg. That's 370g heavier, which would be no big deal if we're talking about a large laptop that's mainly geared towards semi-permanent desk use. But since rMB users value portability, it's a big deal, and the 370g extra weight is a 40% increase. I'd love to see if 12.9" iPad Pro users would happily transition to a model that's 40% heavier.
So, there really is no alternative for users who simply want an ultralight laptop that runs macOS, we need to either stick with an ageing machine or take a huge compromise in portability.
This is why I'm also hoping that there will be an M1 Macbook. I don't think that they'll go as low as 0.92kg again, because of the pure logic of it. In terms of the shell size, they can't go smaller than the rMB, because that'd mean a smaller keyboard, which they're already at the limit for. So, the shell size would be the same or larger. Given that, it'd make sense for them to expand the screen into the bezels, so we'd likely be seeing a 12.5-13" screen, and there's a good chance therefore that the rMB resurrection could be the new 13" Air (one day).
For the M1 MBA, 1.29kg is pretty much the lightest they're able to make it, in it's current design. If we shrunk that machine down to reduce the bezels and hence the shell size, and implemented some design changes, we'd still be nowhere near 0.92kg. The rMB was so lightweight because of the huge compromises, and I can't see Apple - post Steve Jobs and Jony Ive - compromising so heavily again. It simply doesn't fit in with their ideology now, sure Tim Cook pushes design and technology, but it's from a point of logic and safety; he knows that the best bet is to make the lightest possible machine whilst making no compromises in functionality. The functionality comes first, the engineering comes second.
I guess what I'm saying is, although I don't think that we'll see 0.92kg again, I'm hoping that we'll see a 12.9" MacBook Air in the future, a macOS partner-in-crime to the 12.9" iPad, that weighs in around 1.1kg or so. That would be a machine that I could live with, and transition to from the 12" Macbook.