I rode a bike to work for years. My commute was under two miles. This is typical; the average bike commute is under seven miles, and a lot are much shorter than that.
The long distance spandex warriors are numerically insignificant. From a planning standpoint, they are an indicator species. Their presence means that they have a viable migration corridor, i.e. enough decent biking infrastructure that they can actually find a practicable route. Around here, most of this would probably consist of quiet, bike friendly streets in residential neighborhoods, supplemented by a few of the trails that go somewhere useful (as opposed to pleasant recreational rides along the streams and in the parks). When you see the long distance guys on a crowded road where they clearly don't belong, it's usually because there's a gap in the good bike route, and they're flushed onto busy streets until they can dive back into cover.
IOW, when you see the spandex warriors on commuter roads, don't rail at the stupidity of the riders. Consider instead what their presence is telling you. Look at a bike map and see where the gaps are. A lot of the action in DC bike circles focuses on bridging the gaps so you can move easily from neighborhood to neighborhood without killing yourself trying to get across an arterial road.
Don't think of bike commuters as long distance performance artists. Most of them are just moving around their own neighborhoods. A very high percentage of trips by car are under five miles as well. That's an opportunity to reduce congestion, if we can get a reasonable percentage into walking or biking. With good design, biking infrastructure becomes a neighborhood amenity that attracts active young people.
In many areas, you are spot on.
I live in a small town 35 miles from work. Most of it is open interstate. Many of my neighbors work for a big green tractor maker, and drive similar amounts.
The area I live in (Quad Cities, on the border of Iowa and Illinois), is small to medium sized cities with a lot of small towns and rural areas. There is some public transportation but not much.
My family near Omaha is another situation. Growing rapidly, no one in the outer ring of suburbs has had any thought to such things. Or rather, ten years ago they had a ten mile or more gap between Omaha and themselves, so it wasn’t an issue. And Nebraskans really don’t like to give up their cars. There are some decent bikeways there (Better than Davenport, Iowa, who put a bike lane on a four lane street with a speed limit of 40 mph), but again they are in the center of town, and do not extend to far. In fact many of the neighborhoods fight it.