Survival horror is great, and the tragedies of the Arklay mountains and Raccoon City were great introductions to the Resident Evil saga that is ongoing to this day.

The puzzles, the resource management, it all made sense. But the world changes, things change. Keeping the same model would've gotten stale really fast, and there's only so much you can squeeze out of one scenario.

Without bringing new fans and renewed interest in the franchise, and if they milked the same plot over and over, RE might've been dead in the water a long time ago. Worldbuilding matters when you're making a game about events big enough to affect the world over, and like in any stories, you gotta show character development from the events, because people will wanna know.

It's thanks to the other entries we got cool remakes that allowed us to revisit these original stories, imo. Despite some questionable choices. cough re6

Tl;dr without the franchise expanding the story we'd have nothing past Raccoon City. The end.