But sure, if you want examples of this trend try searching Pixiv by title for stuff like "twitterまとめ" [1], " or "Xまとめ" [2], meaning a usually monthly compilation of illustrations that were posted to Twitter first. And that doesn't even get into the artists that stopped using Pixiv completely because they got bored of it or their account was banned.
[1] https://www.pixiv.net/en/tags/twitterまとめ/artworks?mode=safe&... (apparently these links don't capture the fact that it's a title search and not a tag search, you have to be logged in and set it manually)
[2] https://www.pixiv.net/en/tags/Xまとめ/artworks?mode=safe&s_mode...
