That mode of living only works if you primarily travel _within_ the city or to a few well-connected cities in the region.
Travelling from Amsterdam to places without a train station kinda sucks. In some cases, even travelling to places _with_ a train station takes almost twice as long by public transport.
I have a bike. It lets me go almost anywhere in Amsterdam, cheaper, more easily, and generally faster than any other mode of transportation. Sometimes you get a bit wet.
There are a few distances inside the city which are not handy. For those I use the wonderful tram/bus/metro network.
Occasionally I'm lazy and don't want to bike, or need to go somewhere strange. Then I grab a car2go (electric smart car, €.30/min, including electricity, insurance, parking anywhere). When I get to my destination I park it anywhere and end the rental.
Since moving here, my transportation costs have gone from many-hundreds-of-dollars per month for a car/gas/insurance/repairs/tolls/parking/fines in the US, to around €40 month for a bike, public transport usage, and short-term car rentals.
It is much cheaper, and much more convenient, to call a taxi or rent a van when the above options don't fulfill my transportation needs.