It's memory management, not memory minimalism. I'm always hovering about 12 GB out of my 16 GB MBA, but never have any issue opening a project or opening 10–20 tabs (rookie number) and I have a few apps that are always running. I believe that macOS uses the RAM for caching files, so the reported usage is not really tied to the number of apps running. There are memory-heavy workflows, but these are outliers. Even 8 GB would be fine for most of what I do.