The ARC story is about the specifics in one case of development in the high end audio arena. I did not know any specific numbers of hours on anything from Sonus Faber speaker development. But I am sure it is similar, it demonstrates the huge investment that goes into high end audio equipment.
The amount of effort… since very large number of change and listen cycles are involved with engineers with very specific skills… like they can hear nuanced voicing and have the musical experience to understand the objective.