The taxi lobby groups have stopped a train line being built from the city to the airport (20 miles) so cabs are the only realistic way to get home with a 25 minutes journey costing $70.
I've told this story before on HN but I'll tell it again here. On current Google Maps statistics I used lived 18km/24minutes from the airport in Melbourne while the CBD is 23km/22minutes away (faster roads to get to the CBD). Getting a taxi home one time the driver berated me and told me I shouldn't have taken a cab for such a short trip. It wasn't like he was grumpy, he was literally telling me off in the street, after I'd got out and couldn't see his driver ID of course. According to Google maps it takes 3h30m to walk from the airport back to where I was living so I suppose I should have done that.
Skybus is $18, which is not great, but it's better than $70 and it does run ridiculously frequently. It's pretty quick in traffic too, since it uses the carpool lane.
Edit: So long as you can deal with the sometime nausea inducing movement.
The taxi lobby groups have stopped a train line being built from the city to the airport (20 miles) so cabs are the only realistic way to get home with a 25 minutes journey costing $70.