Hey, thanks for playing it, I welcome the more "thematic" criticism! In the initial design we actually did intend for there to be an unstated but alternate win path, but we ended up not being able to implement quite a number of environmental cards, without those we didn't even think this would be possible and ended up skipping the alt ending thing. It's really cool that you found a way to do it anyway, and I wish we'd managed to account for that possibility.
The sewage plant was also one of the cards we realized we'd typoed the numbers on (Especially for cost, I think in the final build it's like $5M when it was meant to be $50M? Oops. I don't think that had anything to do with your strategy though, hah.