You make a great point, and I think in situations like this, it’s an indication you should look for non-economic reasons that the plan is discussed.

Maybe the developer is currying some sort of political favor. Maybe there is some other side reason that is harder to imagine.

Who knows how much bullshit it is, but I saw in some recent discourse that Elon Musk started the hyper loop and boring companies as a way to fight rail expansion. It was never his intention to deliver on the promise of those things, but if they sounded borderline plausible, they could be used to derail train projects.