A lot of things can go wrong during the development of a game. Creatives can be over-ambitious, under-skilled, or just plain negligent. However, more often than not, the thing that truly kills a game can be the overbearing interference of executives, publishers and companies that aren't directly involved.
Games are expensive, so the people behind funding often want to make sure their investment is as "safe" as possible, which results in the compromising of artistic integrity or general shady business practices that would otherwise produce an enjoyable game.
It is perhaps one of the most frustrating aspects of the gaming industry, as these faceless businesspeople appear to lack any awareness or understanding of gamers, resulting in crippling decisions that completely baffle the general populace.
Games are often rushed out to meet deadlines, toned back in response to focus groups, and completely butchered in order to fit bankable trends. Instead of trusting developers, the people who actually relate to the modern gamer and understand the marketplace, execs decide that the popularity of Fortnite means the next plaformer needs a battle royale mode.