Here's a thread about Mac software that happened to
Jump the Shark at some point.
1. MacLinkPlus
When it was good: The utility was excellent back when it was bundled with Mac OS 8.0. The MacLinkPlus was a file translator that allowed your program of choice to open a similar program's file as if it were its own. The version bundled with OS 8 was fast, accurate and transparent - the translation was so good you really could forget it was in use.
When did it jump? at least by version 10, which I upgraded to a few years after getting it with OS 8. This version launched a slow application every time it had to convert a file, and the results were not very good once the translation was done. It was very disappointing to realize the program was now more trouble than it was worth. I think the designers of version 10 tried to code it more cleanly, without resorting to that much extension trickery, but it never worked nearly as well as the old version. I trashed it a few weeks after installation.