The non-reversible nature of the USB plug has irritated countless users since its introduction in 1996. Even its inventor, Intel’s Ajay Bhatt, has admitted that the connection interface’s “biggest annoyance is reversibility.”
There’s a pretty good reason for that, however. A more practical design would have increased costs, making the connector far less attractive to potential adopters.
A USB that could plug in correctly both ways would have required double the wires and circuits, which would have then doubled the cost.
The Intel team led by Bhatt anticipated the user frustration and opted for a rectangular design and a 50-50 chance to plug it in correctly, versus a round connector with less room for error.
It was essentially a strategic choice. Luckily, there are more pleasant alternatives now such as USB-C.