Edit: Your confusion is my fault because of a typo, although it stands to reason that I'm rather knowledgable about night riding so I must have some experience.

I don't ride bike paths at night. That's different from not riding bikes at night. My first night ride was sometime around 1965 with a generator, by the way. My first winter time night ride was much later, around 1978, again with a generator. Actually the same one. That was about my last time with a generator light. But I've been bicycle commuting year around since 1978.

I doubt it. Show us some data to back up the claim. Not raw bike sales, either. That only tells us that bikes have been sold. Not every bike sold has a light nor does it have a generator. Bulk sales of bicycles includes utility bikes as well as recreational bikes. Recreational bike sales are probably higher even in Europe than utility bike sales.

Let's look at some history, why don't we? Generator lights have been around for a very long time as evidenced by my experience. They have also been rubbish for most of that time. The 1965 bottle generator that I owned ran on the sidewall of the tire and had a striking effect on the speed of the bike. Even more striking was the lack of light it put out. You can get a bit more light from the generator as you picked up speed on a downhill...until the lamp blew out. Then you were riding in the dark. If you started climbing a hill, you didn't have light either. If you stopped, you went black. Going black at a stop continued up until the mid90s when someone wired in a capacitor (a small battery really) and allowed the light to work when you stopped for a short period of time. The light was still rubbish since it was based on flashlight bulbs that had next to no output. To give credit were credit is due, the generator part had been improved enough so that it didn't stop your wheel dead when you used it.

Frankly, all of these problems are what drove me to battery systems and I haven't looked back.

The light problem continued until 5 to 6 years ago with the advent of LED lighting. You can now get pretty good light from a generator because the emitter is more efficient. But those same gains have been made in battery driven lights as well. But battery lights have gotten lighter and more efficient as well. And the cost has gone down while the output has gone up. Back in the days of HID lighting, you had to pay around $600/unit to get the same illumination that you can get now at around $20.

And let's not forget that the market that drives high output bicycle lighting isn't commuters but it's the mountain bike crowd. They aren't interested in generator lighting at all. It is useless for their application so there is little market for it.

$20 per unit buys me a light that I will probably replace in 2 years because the technology is changing so rapidly. Paying $60 for a warranty and support that will never be used seems foolish. I've never had to use any warranty or support for any light I've ever purchased. I doubt that most people need a warranty because the lights just don't fail that often.

I bought my first LED light (it was rubbish too) around 2005. They were quickly replaced by a brighter unit in 2008, which were replaced by another light in 2009, which were replaced by a higher output light in 2012 and I don't doubt that the lights I'm running now will be replaced next year because the output and size are changing again.

Having more than one light...having a back up light is a good idea no matter what kind of light you use...drives the price up even further.