Another one of them things that’s always inconsistent - in theory every train in the world has adjustable seats, but it’s only occasionally they bother to add it to the game.
It's perfect for me; any closer would feel too cramped and far forward for me, having to pan the camera down to fit the speedo or other dials is annoying (looking at you 80x fleet). This is why we need an FOV slider, DTG can't cater to everyone so they need to give us the choice.