For the rest of us across the US, the opposite is abnormal. I bike primarily and use the bus the rest of the time, so I'm definitely abnormal. It probably has a lot to do with the costs of owning a car as well as the insane traffice in NYC vs. the rest of the US
I don't agree. Other cities have good public transit, and especially other countries have shown it to be viable. I don't think NY's traffic has as much to do with it as their excellent public transit.
By "excellent" I'm assuming you mean timely and pervasive. I didn't find it very welcoming or clean vs., say, Singapore's public transport. Both are well used...so here, I claim that this is not due to quality as much as it is due to the cost/convenience of using it.
I live in Columbus, OH. It's pretty much one of the most poorly dense, large (800K) cities in the US. COTA, the public bus system, I use frequently because I pay for a bus pass in my tuition. Their buses are generally clean, drivers are friendly, and I feel safe for the most part (people in Columbus are pretty friendly). However, given the poor density the service times are terrible if you're traveling to somewhere other than along the main street. The city is so large for its population that most stops are far and in between. As a result, ridership isn't high at all.
I think convenience...and cost have a lot to do with it.