Yeah there's always a massive difference between who's posting a lot online vs who's just playing and enjoying the game. But you have to calibrate Steam achievements based on who's played the game for more than a few minutes.

The "Eco unfriendly" achievement shows about 60% of people who launched the game played for more than a couple hours, which is quite normal. So out of those, about 30% of players finished the game.

I'm more impressed that only 25.9% have been killed by a moving locomotive ("Watch your step" achievement). Those things are murder-vehicles.

I think it means a majority of players never build rail.