Git follows this model as well, calling it porcelain and plumbing (the internals). Arguably, there’s a third layer in actual GUIs wrapping the porcelain (and sometimes plumbing).

ffmpeg specifically is a bit of an outlier; together with some other tools like qemu.

For the rest of things, you can go a long way by just aligning things nicely, indentation, wrapping/indenting properly according to the terminal width, and maybe adding a bit of bold text which is both easily parsed by machines and human readable.

I generally think these are often considerably more user-friendly than outputting 6 different colours – half of which don't work well on many background colours so it's unreadable – assuming the terminal is 290 characters wide – many tools these days seem to think you've got infinitely wide screens – and all the other things these "modern" things do.

Something like "df" is a simple but classic example; GNU df at least aligns nicely no matter the column sizes (some other dfs, like NetBSD df, don't) and that's still easily used by machines and humans. Maybe -h should be the default though (which would break scripts, so it can't be changed for /usr/bin/df, but in an ideal world...)

Basically, you can have your cake and eat it too.