Concerning the lack of wide spread use of recumbents, I can only talk for myself and about the reactions I gather here in Germany (Beware: Loooong text, enthusiasm at work!):
1) They are mostly high quality products, built by enthusiasts for enthusiasts. This also influences the price. They are not cheap, but they are long time investments. My oldest one is still going strong after 22 years. For decades on end bicycles were considered to be poor peoples transport or toys, a mentality change is only slowly taking place.
2) You need to test ride them thoroughly to get hooked. Test driving looks and feels quite weird at first, because a bicycle is in fact a pendulum upside down, i.e. the further up the center of gravity, the slower they wobble from side to side and the stronger the gyroscopic stabilization by the wheels. Because of the low center of gravity your first rides on a recumbent bike tend to be a very shaky affair which usually deters casual testers. This, of course is not the case with trikes. Presently, trikes are the best sold kind of recumbents.
3) You use different muscles and a different motion sequence when pedalling, so you get the feeling to have "rubber legs" at first. Takes some time to got used to it.
4) They are not allowed in official bicycle racing since 1933 when a mighty lobby of manufacturers of standard bicycles coerced the UCI (Union des Cyclistes Internationale) to forbid recumbents which only were built by some very few small manufacturers, yet grabbed all the speed records. Thus, there is very little media coverage of recumbents and the speeds and distances achieved with them:
"On land, the speed record registered by a rider on a 200 meter flying start speed trial was 133.28 km/h (82.82 mph) by the Canadian Sam Whittingham riding the Varna Tempest, a streamliner recumbent bicycle in 2009 at Battle Mountain, Nevada. His record has been surpassed by 0.5 km/h by Sebastiaan Bowier of the Netherlands in 2013 setting the new record of 133.78 km/h (83.13 mph)." (Source: Wikipedia).
This speed is probably unattainable with any conventional bicycle. The 24 hours single rider record distance is at some 1250 kilometers, done by my recumbent riding buddy Christian von Ascheberg on a high speed closed oval circuit. This probably is not attainable by any conventional either. (Sorry Sniffles, it´s that speed thing again!)
Still, those remarkable achievements never found their way into the official cycling publications.
5) In Europe they are closely connected to the rising of the "green" movement of the late 1970-ies, so the got an "eco" image in a derogative way.
6) Yes, visibility can be a problem, but there also are "high racers" where your eye level is the same as with drivers of normal family saloons.
7) Children laugh, teenagers scream, middle class citizens produce pejorative comments, dogs yelp their lungs out if you pass by on a ´bent. You have to develop a healthy self-consciousness to grin and bear this.
8) Because you are faster than a standard bicycle, but slower than cars you have to be either very relaxed on crowded cycle paths or fairly self-confident on roads. Best way: Go by some narrow side lanes, they are more beautiful as well.
9) You can´t go off-road with most ´bents, but they are a beautifully relaxed way to do you every day commuting on cycle paths or public roads.
I got no problems with all that, because I know my reasons to ride my ´bents and also because I prefer to belong to a thoughtful minority that if necessary goes against the mainstream. Until they come into more wide spread use, you can´t keep a low profile on a recumbent.
My main reason for bents probably is a bit unorthodox: I used to have a beautiful long-distance touring bicycle, but I always disliked that feeling of numb fingers and a painful neck after a long daytrip due to the position you have to take on a bicycle with a racers handlebar.- Also, I am addicted to my guitar.
When I first sat down on a recumbent, my hands spontaneously found the handle bar beneath the seat and my hands and shoulders felt very relaxed. I instantly knew that this was the way to allow for both long distance cycling and guitar playing without compromising one of them. I was hooked and have been ever since.
Another point for me: On a racing bike you tend to look at your front tyre or a very few meters ahead. On a ´bent you lean back and your sight line is parallel with the ground: You see a lot more of your surroundings, which relates to Sniffles´ beautiful landscape pictures again.- Just to pick up the original purpose of this thread!
Next point: A racing bike saddle is a hard and narrow thing and the biggest part of your body weight is concentrated there. At the same time, this is an area of your body that has been put into a protected position by mother nature because of it´s very high sensitivity. No numb feelings there if you ride a ´bent!
If you want to see a very special kind of recumbents, search for "velomobile" on youtube or anywhere on the net. Those are fully faired monocoque trikes, aerodynamically shaped, made to go long distances in a fast, relaxed way, all year and in almost every kinds of weather. On the downside, they are heavy, around 30 kilograms or more so their preferred "habitat" is level country with potentially strong head winds and lots of rain like the Netherlands and the baltic states where they found the most wide spread use. I know quite some velomobilists who got rid of their commuting car, because they did not need it anymore, having bought a velomobile. No taxes, no fuel costs, spare parts are cheap, repairs can be done at home and there is physical exercise too.
A well trained velomobilist can do 200 kilometers a day without resorting to electric assistance or fossile fuels.
In August 2011 a group of about 50 velomobilists has traversed the USA coast to coast from West to East in about 4 weeks, some 5.000 kilometers distance. This was called the ROAM "Roll over America Marathon" and must have been an incredible experience for all participants.