I think it’s because Incom didn’t make the TIE fighter. Seem to recall the X-Wing was supposedly created for the Empire and they decided not to buy them.
There is the
which sort of spoils the naming.
I guess that’s because the name came from a novel in 1979. I have a feeling the picture is just an early Ralph McQuarrie sketch of what became the X-Wing design that was then repurposed as an older starfighter when they made the RPG and stuff? It definitely fulfilled a sort of requirement in the RPG world of starfighter ‘scooter’ to the X-Wing’s full on Harley.