That's not what alternative means. A passenger train is an alternative to a bus, but you can't drive a train on a freeway. "Alternative" in no way implies "feature parity". Getting addicted to meth and dying in a shootout with the police is an alternative to completing a medical degree and retiring to the Poconos, but they do not fill similar functions.
To be fair, I think it's pretty reasonable to say that walking 50 km isn't competition to taking a bus, but just an alternative. To be competition, it would have to be a _good_ alternative...
