I think reducing social anxieties would reduce the prevalence. People would no longer feel the need to use fake identities to hide behind while expressing themselves in the truly authentic way they would like to.

Taking on a fake identity among other people also taking on fake identities comes with an unwritten consent between all participants to activities and behaviour that is not what you would usually see. It's an unwritten agreement between all participants that says "you can behave the way you want to behave around me and you will still be accepted for it". This agreement changes slightly between each community, but someone in cosplay at an anime con is generally consenting to other people in cosplay attempting cosplay interaction with them, this unwritten agreement is pretty similar in all scenarios where participants assume roleplay identities.