While the days of burying cartridges in the desert (looking at you, Atari) are long gone, that doesn't mean developers don't continue to call it quits on their games, albeit in a rather less ignominious manner than in the 1980s. It's pretty difficult to dump the internet into a landfill site, after all, and if anybody tried to pull such a stunt, Reddit would be all over it in seconds.
Developers inevitably hit bumpy roads on their journeys through a game's life cycle, be it licensing or monetary issues, superior competition or simply creating a buggy, unfixable mess which they had the audacity to charge people money for alpha testing. Rather than spending further time working to iron out these problems, sometimes it's easier to concede defeat and give up on games as a bad job.
Then again, some games achieve wild popularity, media coverage and player bases, but are still abandoned for various reasons. Sometimes it's after a few years, but occasionally they get dropped faster than a General Studies A-level, despite being infinitely more interesting and arguably more useful.
The list of instances is innumerable. However, the word count is not. The following examples provide a selection of the myriad circumstances that lead to a game disappearing off the shelves and into the murky recesses of forgotten things, alongside old exercise equipment, every single one of our New Year's resolutions, and the Cheeky Girls.