Nope you are not missing anything
Fares based on distance or time (also expenses based on them) was something spoken about, but they never went into proper feature requests, thus never worked on.
At the meantime, lots of us developed automated fare stuff for our selves, thus not thought about it in general anymore. I had something built in my module, technically based on distance, tried to implement it in v7 but latest changes done to fare logic was making it tricky to implement, so I stopped working on it.