US built frames cost a fortune in comparison with those in the UK. That seems to me largely, but not exclusively, a result of the huge amount of time expended in profiling and shaping lugs.
Since this craftsmanship isn't exactly on the same level of complexity as quantum theory, I would submit it is achievable by gifted builders prepared to spend similar amounts of time and attention to the task.
UK builders are quite capable of that but the home market does not demand what would be seen as an unnecessary expense.
I was recently asking myself this same question. Why is it that the British makers seem to be able to offer a frame for less than it would cost me in materials in the U.S?
There are some reasons for this. It depends on a case by case basis, some of the companies have had there equipment paid off for decades. The cost of living can be substantially lower in some areas than the average in the U.S. There is no need for product liability insurance, some of the builders of classic frames are older, have pensions and the like and do not need to make much of a profit.
The frames can differ too. U.S. builders tend to have sophisticated fixturing and tools whereas British builder often do with much less, silver brazing is prevalent in the U.S, stainless, expensive painting procedures using Imron, not just enamel etc. I am not debating the merits of these differences, just pointing them out.
Its the little details that can really start to increase the prices through higher materials cost, tooling and time. I am surprised that this detail may be seen as a unnecessary expense. This from the country that brings us Aston Martin, Jaguar, Rolls Royce. All highly unnecessary but thankfully still produced.
Just an opinion
David Bohm
Bohemian Bicycles