Because she's in a grey area
[21:28:36] Rosalina's Chiko: Mario, Luigi, Peach, Bowser (and Yoshi and DK if you want to count them) are characters that have been around for generations.
[21:28:47] Rosalina's Chiko: Literally everyone knows them
[21:29:12] Rosalina's Chiko: And they appear in nearly every game
[21:30:05] Rosalina's Chiko: Rosalina was a character that was intended to only show up in Galaxy, but got made a part of the main cast due to astoundingly positive critical and fan reception.
[21:31:04] Rosalina's Chiko: While she's really popular, she isn't known by absolutely everyone, as much as I hate to admit
[21:31:56] Rosalina's Chiko: She is a character with a huge fanbase, but nobody outside of that really knows who she is, unless they are Smash fans or something
[21:32:24] Rosalina's Chiko: So they make her scarce to get her fanbase rabid
[21:32:41] Rosalina's Chiko: Hence, the bum rushing you've been hearing about all day
[21:32:52] Rosalina's Chiko: She completely sells out
[21:33:19] Rosalina's Chiko: Then when the Super Mario version comes out, everyone is gonna buy that too, but it will be more plentiful
[21:33:32] Rosalina's Chiko: Basically, they don't want people to just buy the Smash one and ignore the SM one.
[21:33:56] Rosalina's Chiko: They couldn't pull this off with other characters, as they are too well known.
[21:34:18] Rosalina's Chiko: Sheik is kinda a similar case with the Zelda cast, except she likely won't get a second figure
[21:34:37] Rosalina's Chiko: Sheik is only in Ocarina of Time, Smash, and Hyrule Warriors
[21:35:00] Rosalina's Chiko: She's got a huge fanbase, but only Zelda fans and Smash fans really know her.