Why do we rarely see recumbents and almost never see velomobiles? Recumbent bicycles are more efficient than ordinary upright bicycles, and velomobiles are even more efficient. Then why do we see them so rarely on the road? Is it because they are expensive, or are there some non-financial, significant disadvantages?
Talked to a guy who had a velomobile at a local charity ride. He said the thing cost $5000. Recumbents, while not as expensive as velomobiles are also quite expensive. Usually over $2000. That could be part of the reason. Sure, with economies of scale, they could be made cheaper, but that's kind of a chicken and an egg problem.  Also, even though recumbents and velomobiles are so much more efficient, they do have quite a few of their own problems.  Because they have so much extra weight, they tend to be quite a bit slower on the hills. Many people also don't like being so close to the ground.  I like being able to stand on my pedals and see over most of the cars when riding in traffic.  Also, regular bikes are pretty efficient these days. For $1000 you can get a pretty good bike. And one last thing. Don't underestimate the "conformity" factor.  Many people don't want to be seen as weird, or outsiders, and want to fit in with social norms. Riding a bike is already going against social norms in many places. For some people, having a recumbent just takes things a bit outside their comfort zone.