Matt Ball posts The Forgotten Delicious about his criticism of the delicious generation where apps are created with huge hype only to effectively stagnate and die.
He describes the typical programmer behavior of losing interest in a project once the "fun" part is done (scratching the "itch"). It happens to me, I'm sure it happens to most others as well. There are those programmers who find creating the code to be the enjoyable part. For them debugging, for example, just ends up being a chore and something to be avoided. Other things like documentation can also be categorized as unenjoyable but is often necessary.
From a business standpoint it could also be that the applications released weren't actually profitable and a new direction needed to be taken. The applications mentioned in the article are at the same time both incredibly niche and incredibly inexpensive.
In defense of the AppZapper creators, was there much that actually needed to be done? It's not as though the software offering was incomplete in functionality (I assume, I haven't actually tried AppZapper).
