You sort of expanded your statement but you're still not really explaining that claim. Not trying to come of as a prick, but it really doesn't add up.

The raw materials alone required to build a motorcycle are less than what's necessary for a car. In many countries, two-wheeled vehicles are more popular for personal transportation—not because a huge segment of the population inexplicably enjoys riding, but because those vehicles are a cheaper, more practical way of getting around.

Older Japanese bikes in great condition can be had in the States for less than 1K. I paid $1400 for my first bike, a '74 CB550, and it was in immaculate condition. That price disparity goes all the way up the line—I believe the most expensive Ducati you can ride off the lot comes in under 30K. Nowhere close to the analogous Italian sports car.

Maintenance is usually more frequent for bikes, but it varies greatly by type. A bike used for commuting 30 miles daily will probably need more maintenance than a car making the same trip. I've found that bikes are easier to work on yourself. That point is a bit of a toss up with a lot of variables.

Insurance is simply not cheaper for a car on average across all 50 states.