"Jumping the shark" is a term first popularly used by critics to denote that a TV series had seen its best days, and is now steadily declining in popularity, and most of all, quality.

Plenty of TV shows tend to have good 1st seasons, somewhat acceptable 2nd seasons, and from then on, it usually goes downhill.

The same can be applied to game developers. Take, for example, Squaresoft (now Square/Enix). In the PS1/PS2 days, they were undoubtedly the RPG kings, churning out many classics such as Chrono Cross, Parasite Eve, Xenogears, the Tales series, Front Mission, and of course, Final Fantasy. This generation, however, they seem to have fallen so far that they hardly seem to matter anymore in the grand videogaming scheme. The only Square game I've somewhat enjoyed thus far this gen is FFXIII, and even that is a fatally flawed game. FF14 so far has been a major disaster as well. To me, S/E definitely has jumped the shark.

Can you think of other game companies that have suddenly, sometimes inexplicably, taken a big turn for the worse?