Because most likely (at least according to Hanlon's razor) they somehow decided that using Google Drive as the only persistent storage backing AI studio was a reasonable UX decision.
It probably makes some sense internally in big tech corporation logic (no new data storage agreements on top of the ones the user has already agreed to when signing up for Drive etc.), but as a user, I find it incredibly strange too – especially since the text chats are in some proprietary format I can't easily open on my local GDrive replica, but the images generated or uploaded just look like regular JPEGs and PNGs.
It probably makes some sense internally in big tech corporation logic (no new data storage agreements on top of the ones the user has already agreed to when signing up for Drive etc.), but as a user, I find it incredibly strange too – especially since the text chats are in some proprietary format I can't easily open on my local GDrive replica, but the images generated or uploaded just look like regular JPEGs and PNGs.