I don't know about Australia, but Netherlands is basically a flat country where its tallest mountain (hill?) is 320 meters above sea level. Therefore, cycling is particularly easy.
And things are often at reasonable biking distances. Here in Palo Alto the city is flat and the weather is even more agreeable than the Netherlands, however, people mostly drive because they either live in a different town and commute to Palo Alto, or they live in town and commute somewhere else.
Longer distances make it a bit harder, but they can work if there's an integrated cycle-path network, and ideally some integration with transit. For example, Palo Alto to Mountain View is only 6 miles (10 km), a distance that's very common to bike in Copenhagen, and yet nobody bikes it in the Valley. Part of the issue might be that there aren't great routes. You either bike down El Camino, a rather intimidating proposition, or else you have to piece together a complex route by weaving through residential neighborhoods.
The bike->train->bike option can also increase the practical bike-commuting area, but it's hampered by Caltrain not running often enough or to enough places.
I made the Palo Alto <-> Mountain View ride 4/week for four years. My ride was bout 9 miles, which is longer than I'd expect most people to ride, but I couldn't afford to be closer.
Biking on the same roads as cars is generally not fun. I first used Middlefield most of the way, but that meant biking in with the cars. It wasn't until much later that I discovered Bryant street, which prohibits through motor traffic but allows bike traffic through. It's pleasant enough, but you are still sharing a road with cars and I've seen many simply blow through the stop signs on those residential streets (there are rarely any other people around anyway). Even with Bryant, half my ride was on a major auto thoroughfare.
The position of bike lanes on American streets is stressful for bicyclists. You basically have cars on either side. On one side you have cars driving and who want to make right turns across your lane. On the other side you have parked cars with drivers-side doors that completely block the bike path when open. These people also want to cut across your lane to enter traffic.
In my roughly eight years of bicycling around the bay area I've only been hit once by an auto, and that was one where he was fully at fault for making a left turn into me when he acknowledged he saw me in the opposing lane and thought I was slowing for him (I slowed because it looked like he was going to turn without having right of way). It was low speed and I wasn't injured. However, bicycling around the bay is not fun, despite having a few decent bike paths.
I've also biked in Amsterdam and I can attest that we have a long way to go. I believe we need to change our cultural attitude towards bicycling first, then the rest will follow.
This is true, NL is a small country and we really have to be conservative with our space. I was amazed to see, when I was in the US, how widely spaced out everything is, especially the suburbs. Those distances do add up quickly and perhaps make for less interesting bike rides. I'd probably still get one if I lived there, just because it's easier to get around for small distances, but I've heard for some people the nearest supermarket is a few miles away, then yeah, going by car makes a lot of sense.
You can't easily change such geographic/cityplanning type of differences either, I think.
It takes a long time. Vancouver, BC was very successful with this because they built a new transit system back in the '80s (Skytrain) and then clustered density around the stations. It's been extremely succesful, and there is also a complimentary system of bicycles boulevards for people to ride bikes.
Here in the US, however, the car rules, for better (but mostly) worse. I had an incident on my bike last Monday in Palo Alto with a car where I fell and broke my hand.
Trying to code with a broken hand is rather... interesting.
