That has been a sobering thought for someone who's a fan of Melee's competitive scene. There were already widely circulated rumors during Melee's early life.
The Sonic and Tails in Melee hoax for example (oh man, anecdotally I remember this and the Toad im Melee rumor pretty vividly, some believed those):
And if Marth / Roy had been Japan-exclusive those rumors would've likely been much more intense. Not to mention that some Americans / Europeans would've likely travelled to Japan or bought Japanese GCNs to test Marth / Roy out if that was the case.
Suffice it to say, I don't think that FE would've remained Japan-exclusive in that scenario either.
Besides what Gwen said: He's going to be okay, don't worry. Smash immortalized him in a way.
Nintendo and Sakurai's already reintroduced him via DLC once: