I have a different theory; perhaps line printers (which terminals try to emulate) are to blame.
Space on a line is limited and one directional, so thr tools naturally evolved towards strange single line incantations instead of full fledged programs.
Commodore Pet did it right by introducing a navigable terminal where you could move between lines and don't need to open an editor to write multiline programs.
This was already a solved problem in the 70s. IBM's 3270 series offered full buffered access to a character matrix display, and DEC's VT52 and later terminals added bi-directional scrolling.
Modern CLIs can usually emulate at least a few of the old scrolling character matrix displays, but only a few bash commands (e.g. top) use the extra features.
Space on a line is limited and one directional, so thr tools naturally evolved towards strange single line incantations instead of full fledged programs.
Commodore Pet did it right by introducing a navigable terminal where you could move between lines and don't need to open an editor to write multiline programs.