Blockchain used to be a good money laundery company, you think they don't know Shared Send is using for money laundery when they build it?
Recently FBI pushed them very hard (Shrem arrested) that's why they deleted Shared Send and also start loging user's received and destination address of Shared Coin at system background. there is no needed to mix many transactions together, because Blockchain will just show all of your receive/send logs to the goverment when asked, the same will happen with Shared Send (if its still exist)
That's a bit too many assumptions for me to be comfortable accepting without evidence. Have any?
Granted, it's probably safe to assume that any kind of centralized solution is not a solution at all.