I understand what you are trying to say. Yeah, Marth is far from disliked overall.It helps him in Japan, but doesn't help him outside of it, since he wasn't "first" outside of Japan. It's likely why in the Choose your Legends votes he gets a core voting block, but then when the previous winners are ruled out other characters then go and jump ahead of Marth. These aren't suddenly people's favorites, it's just when being unable to vote for their actual number 1, they still put them ahead of Marth.
It doesn't help that although he got a localized game it was one where they decided to stay pretty close to NES level storytelling (there were some additions, but it was still a very minimalist story, unlike the full revamp that Gaiden/Echoes got) and had really bad overall aesthetics.
But let's be real, they only brought up Lyn being first for western audiences to deflect from her sharing one of the most common arguments for Roy not "deserving" his popularity.
It is interesting though that both Roy and Marth were first for western audiences through Smash, and Roy is noticeably more popular.