Pantographs will work only when the vehicle is constrained to a single lane of travel. Which might work okay for some bus rapid transit situations.
Otherwise the pantographs will go out from under the wires as the vehicle changes lanes, that is, the pans will dewire.
Now I suppose we could have multiple parallel wires say 5 feet apart alternating positive and negative and the pan switches to another wire as the vehicle changes lanes anywhere along the route. But the pan has to leave one live wire before going under the next live wire* to prevent a short circuit and the result will be a momentary loss of power which is not good.
* The parallel wires would actually be something like positive, dead, negative, dead, positive, dead, etc. and the dead wires keep the pan shoe on the level to go under the next live wire when changing lanes but we still have the problem of momentarily loss of power.