Scrivener 2 has been removed from the Mac App Store to make way for Scrivener 3...
Scrivener 2 No Longer Available on the Mac App Store
In case you're looking for it and wondering where it went: we have now removed Scrivener 2 from sale on the Mac App Store ahead of Scrivener 3's release tomorrow. Scrivener 3 will be available on the Mac App Store at some point in the future, but will initially only be available on our own store. (We had planned to release Scrivener 3 on the App Store at the same time, but it has been stuck in review longer than we had hoped.)
If you bought Scrivener 2 from the Mac App Store, don't worry: you can still download and install it whenever you want. Simply visit the "Purchased" tab in the Mac App Store—Scrivener 2 will still be there.