[Kamatayan]

The reason alter ego characters aren't produced as much is because they wouldn't appeal to the target demographic, the kids.

A lot of collectors create customs of alter ego's of figures they own like Peter Parker or Tony Stark. Figures occasionally come with swappable heads of their alter ego's so a lot of people buy duplicates of the figure so they can have them with the mask on and off. People also put the swappable heads on body molds that they believe fit the character's regular attire.