The existence of an 8GB laptop in Apple's product line was also absurd in 2018.

That might be your opinion, but it isn't out of line with their competitors. You don't have to look particularly hard to find other premium thin-and-lights at 8GB and a ~$999 price tag. I think that is ridiculous, because the Air is better than all of them.

fwiw the memory bandwidth is so high on these devices that it doesn't feel as bad as it should be.

Memory bandwidth doesn't matter for these types of devices, it is memory latency that matters. But best of all is actually having your application in memory and not having to do disk reads.

Most usual applications (native) runs under 100MB of real memory. If you're insisting on using electron apps from developers that does not care about performance...

Thats great for you I guess. When I work, I want vscode with all the fancy linting and language server bells and whistles. I want to be able to have a ton of chrome tabs for browsing and docs and I want a local version of whatever I am building to run. Im gonna make the bold assumption that this is quite common in the dev community. Given that, 8gb is pushing it, no matter how you spin the "but my memory is fast" or "but native apps"

Huh? High memory bandwidth doesn't help at all if you're running out of memory.

It does when you have very fast solid state storage beneath it. Most computers make use of swap. If the performance gap between swap and ram is small, you will feel like you have more ram than you actually do.

And what relevance does that have with memory bandwidth? Of course a faster SSD helps if you're swapping, but you said faster memory bandwidth is what's making the tiny amounts of RAM on modern Macs "not as bad"

If you had said "the fast SSDs make these tiny amounts of RAM not feel as bad" I would've agreed