When you design a game, on paper before writing a single line of code, you have to think about marketability

That's funny, I would consider a theme or concept before asking myself how I'd sell it. You can't sell something that doesn't exist.

You have to think "Does my game need a relatable main character? Who is my target audience? Kids? Adults? Horror fans? Adrenaline junkies?"

That's better.

Often times, other mediums like movies and television shows can be written, produced, completed, and then marketing kicks in. Ex: Edge of Tomorrow.In game development, this is simply not the case. Very rarely do you see a game get produced where the designer did not think about marketing during pre-production (Flappy Bird is an example of such a rare case).

Minecraft.

Grand Theft Auto, originally Race n Chase. It was a hit because of a bug in the programming.

IIRC Goat Simulator started out as a dev fucking around, or learning dev. Something along those lines.

No game studio designs a game, finishes pre-production, begins development, and then considers marketing or hires a marketing person/firm.

That's not true. I am one of those people, and I am currently working a client who's never thought about how to monetize their game until they came to me. And it's in Beta. That's the reason I'm subbed here, to better understand what my client is doing.

In case you didn't notice, this sub has a Marketing Monday thread for a reason. Just because a more specific sub and a more general sub both exist, does not mean this content must not be allowed in this sub.

Did you not notice the thread you're posting in? Complaining about too much marketing content...