They mention Ys IX there. That's it, Adol is CP11.
Okay this is just false.
If that was the case the GBA FE games, the Tellius games and the remakes of Marth games on the Nintendo DS would have sold quite well. But that wasn't the case, those games overall sold poorly, I think the GBA games were the ones that performed better but that's it. To the point that they decided to not localize FE12 (the second remake of Marth's story) outside of Japan.
Fire Emblem started doing better when Nintendo decided to actually promote the series. Which happened with Fire Emblem Awakening on 3DS, who basically saved the series and by the time we got Lucina and Robin in Smash 4 2 years passed between Awakening and their inclusion, so there's no way Smash helped Awakening sales in a significant way.
Smash exposure definitely helps, but it has never been the main reason for the growth of a series already present in Smash.