All four of which users are enjoined, over and over again, not to try to parse the output of (particularly ls). That is, those are the tools specifically not meant to be connected by pipelines, but merely used for operator convenience.

...But how do you extract that data otherwise?

Instead of ls, find. Instead of ps, you parse the nodes in the /proc filesystem that ps itself parses. Ditto the /sys filesystem and du/df.

When those tools were written, /sys and /proc didn't exist.