Not getting salty about it, I'm just curious because this is the first time it's happened to me. Maybe I've just always been super lucky, but normally they at least pretend to ship the next day and mark it as such. Shot the guy a message about it but didn't get a reply.
Depends how large a vendors operation is. Larger vendors sometimes have designated shipping days like only Mondays etc..
Also if they are lazy or not very professional. Vendors usually don't like to give out shipping dates.