Because it doesn't help sell another SKU? Of course not. If the Xwing is so broken and they're so concerned about its absence in competitive play they'd have FAQed it ASAP for tournaments instead of upselling the "fix."How about they just FAQ it to add one hull? No purchase necessary, no replacing droids, no titles.
Developers have stated in the past that that is a road they are unwilling to go down
Because changing the rules in errata is a god aweful, cludgy, stupid way to fix a game that leads to bloated, confusing, unbalanced, incomprehensible rule sets that require a whole new edition of the game and a reprinting of everything released for it to bring them back into comprehensibility.
Ask an old school star fleet battles player what they think of errata. Ask a Warhammer player how well errata works to fix balance issues
Errata is to be used only as an absolute last resort and to fix typos.