The TIE Interceptor's stat line cost efficiency is actually a hair higher than the X-wing.
And the TIE Interceptor has boost and barrel roll, so if the PS1 Interceptor isn't viable, then the PS2 X-wing certainly is not either.
So, it seems as though (inherently flawed and limited in scope) mathematical models are once again declaring ships to be entirely "not viable".
It's this kind of cynical, statistic-driven analysis that has led - over the last 12 months - to a self-fulfilling prophecy of a meta. Entire ranges of ships, pilots and upgrades are ruled out wholesale because they're considered (under the said inherently flawed and limited in scope model) to be marginally less "efficient" than their cousins.
New players pick up the game, gaze in awe at the wealth of options available, join a forum to find out more and are told "yeah, don't use that unless you want to lose."
TIE swarms became the norm because we're told they're "efficient". BBBBZ becomes the norm because we're told it's "efficient". At the expense of everything which is apparently not.
This (incredibly well designed and balanced) game is packed to the brim with an absolute wealth of options and variety, and yet the dogged pursuit for perceived optimum "efficiency" appears to be stifling those options and killing off that variety. So here's a novel approach: to hell with so-called mathematical efficiency; whatever happened to fun?