Motorcyle ownership is popular throughout the US, but probably the most daily (or at least frequent) use is in rural and semi-rural areas where a bike is much more economical than a farm truck for frequent reasonably short trips. The criteria probably are moderately long distances for "local trips" and sufficienly moderate traffic to make it "not too dangerous."

We have lots of places that meet those criteria in my central plains area.

It's been some time since I've travelled to any "megopolis" areas, but some years back bikes were pretty sparse around Los Angels and/or Dallas/Fort Worth, at least on the major highways, because of extemely high auto traffic densities, high speed limits, and resulting high density of stupid drivers. I also don't recall seeing many in Boston, since it's hard to ride slow enough to mix with the congested traffic; but that was decades ago.

Cycles, mostly Harleys(?), are very popular a little south of my town, because the few roads are good but it's a "flood plain" region where most local roads are "intermittent" due to numerous little watercourses. Towns of reasonable size are 20 or 30 miles (25 - 50 km) apart, which is a nice ride.

Cycles appear to me to be less used in a North Texas area we visit, probably because the average distance between towns with "useful amenities" is 70 miles (110 km) or more, which is a bit far to go unless you're after a load of groceries bigger than you can reasonably carry on a bike. Prevailing high and gusty winds may also affect that area, but I don't think that's a real barrier to the bikers.

John