Earlier quoted context omitted.
How is that not a natural sentence? I think people are reading into stuff. That's just good writing. Could it be generated? Sure. But there aren't the obvious tells you act like there are.
Here's the context: "We underestimated the gravitational pull of existing platforms. Network effects aren't just a moat, they're a wall." It's a mixed metaphor which doesn't make any sense. There are really very few ways in which this can be considered good writing - I guess the grammar is ok even if it is nonsense. So let's break it down - underestimated the gravitational effects - ok, this is nice, like where it's…
Also werent all "moats" commonly paired with a wall in real life? As in a moat around a castle wall?