Ah then here's hoping they trim it down a lot more in the future. I imagine a lot of it is because of keeping track of generated NPCs, so a fix for that might be if they only stored NPCs you've had meaningful interactions with, and never generated any NPCs except when you visit a location. So Daisy X is generated when you go to the street, but if you haven't asked for their number or had sex or whatever, Daisy X is immediately deleted when you move beyond the street, and Paul Y and Daisy Z are created when you load the next location, etc.It is an issue with the game.
The save file bloat is massive. It's not as massive as it once was, but it's still massive.
Also, make sure you disable autosaving. Saving and loading takes a really long time.
That or go extremely dark and allow players to kill anyone they encounter. This game has guns after all. Then you choose your own minimum of npcs generated, even down to creating a ghost town apart from the preset story-involved npcs. I wouldn't be particular to that option, but.. it would be an option.