Maybe because Cyberpunk's debacle? You know, hyping a game to absurd levels.
Heard that reasoning a few times already, still dumb as fuck. Games live and die by their hype, the only mistake Cyberpunk did was being broken as fuck. Even today people bashing on Cyberpunk 2077 for its story and design are in minority, most people don't care. Had they delivered a workable game and didn't promise things that aren't in game, then it would be a game of the decade and idiotic players would swallow it all without a whine. But CD Projekt was too greedy and incompetent for that, and paid the price.
Bethesda also has their history with dumb promises, like Todd's famous 'you can climb every mountain' or 'sixteen times the details.' They are also insulated from criticisms thanks to their reputation of 'buggy games.' The fuck-up with Starfield would need to be beyond Fallout 76 for it to matter.
No, the lack of hype is all on Bethesda and their advertising teams. They don't have a single notable feature to sell the game over, or if they do they fucked up the presentation of it. The leak said that:
-throughout the systems you can offer refugees and other people to start a new life in your colony. once they're there they will start setting up shops and if you build a landing pad traders aswell as new colonists will come visit your colony. Theres much more to talk about that stuff since itll be one of the biggest marketing selling points for this game. If you have more questions feel free to ask. Once you completed the first tutorial quest you can start building a colony pretty much on every planet/moon.
So they want to sell the game on their new settlement system. Sounds thought out, but I don't like it. People don't buy Skyrim or Fallout 4 to make settlements, they want to explore and bash things on their heads. Imagine if Skyrim's main selling point was building a house to live in, it wouldn't sell even half its copies.
To summarize, there is no mastermind at Bethesda taking care to not over-hype the game. Such thing as over-hype doesn't exist, only extremely botched products. They fucked up in marketing, that's all. Some office rat at Bethesda is probably checking engagement metrics right now and sweating, seeing that the game hasn't done enough waves on the internet. It's likely to be fixed in incoming months, better marketing, more selling points etc.
But so far, they fucked up. It's not a big fuck up, but it's there.