Originally Posted by
Miele Man
I guess it's hard to make a light with a long but road & road shoulder width beam that doesn't have a lot of upwards and sideways spill.
It's not hard, it is just expensive (and time consuming). There is plenty of expertise in this topic from automotive industry worldwide and in europe, viz germany, also in the bike industry. Designing proper optics with cutoff costs ~20.000 USD. And that does not necessary include the costs for the tooling required to produce either the lenses or the reflector. And you have to design the optics specifically for your dedicated light source (especially the emitting area).
The more light you want to have, the more expensive the design process becomes. Since sales numbers for bike lights are much lower than for car/truck lights, the cost of the design per light sold is not irrelevant.