Does anyone know the reasons why USB was not made backward compatible with RS-232? It would only take a very short negotiation to determine if both endpoints support USB.
To expand a bit, the typical fully compliant RS232 setup has a special level translation IC (for example the MAX232) to deal with the huge voltage range and convert it to something more low voltage digital logic friendly. And that IC usually requires power supply levels that the typical cheap USB device would not have, which means it would have to add more circuits to generate them, adding even more cost to the hardware.
And the USB committee probably figured to be not fully compliant with RS232 would just confuse people, and damage hardware, so it was better to be not compliant at all.
But...
> And the USB committee probably figured to be not fully compliant with RS232 would just confuse people, and damage hardware, so it was better to be not compliant at all.
...you are sadly right.