Even with macOS deep into swap space during development (about 6-8GB of swap), macOS internals will happily keep 2GiB of memory reserved for window management and spotlight.

Apple's fast SSD is the only reason this laptop doesn't get bogged down under load, and with it being irreplaceable I wonder how long the disk last being used like this.

Obviously you're not going to use Apple's new netbook to do heavy development, but I don't expect the base model to remain usable for long with only 8GB. I don't exactly get the impression macOS has gotten lighter to run over the years.

Very bad truism that's not even compatible with the first half of your post.