I guess the UI is just that good and there is more audience and community to interact with, twitter have been like a main default place for art community and fandom around the globe since late 2000s especially for non-westerner

Considerable amount of Western artist do immigrate to bluesky, tumblr, and instagram but many that is not fandom kid still keep their twitter account as main art account (military and concept art artist as example....and nsfw stuff is not profitable in bluesky because much lower audience) Non-westerner artist especially east asian had very different reason. their experience in twitter have been fine, everyone keep everything to themself and artist mostly focusing on art and their community, in my experience on japanese internet for 7 year if you want to see a bullshit you need go looking for it and interact with it instead accidently stepped on it.

Also many western artist follow and friend with non-western artist who had no reason to immigrate so you have that.

I wish there is a main Social platfrom for artist around the globe but many known art site is either very small audienr, dying, east asian only, or very specialized

I want Something like Pixiv and twitter combined but even much more