Like, you've got an engine, which you paid a bunch of money to develop. But you're only making one game at a time in it, which limits the return. If another carefully-selected studio were willing to use the engine and had Fallout rights, they could put out a game. You did that with Obsidian and Fallout: New Vegas was an enormous success.
They do need to refactor their cell framework to support real-time streaming for interiors or cut down the load times to near instantaneous because modern titles do not need to have such long loading times apart from the initial load when the game boots
Loading times aren't getting smaller. Textures, sounds and other files are getting bigger, and regardless of how well optimized you make your engine load assets, if those files are big your device CPU is going to take longer to load them into RAM.