The copying of other's designs is certainly not a new phenomenon. However, given the hugely competitive manufacturing market of the world today, and the lack of respect for copyright laws in some of the emerging manufacturing countries, it is a growing problem for lighting manufacturers.
As a designer and manufacturer of decorative lighting fixtures for both commercial and residential markets, I am acutely aware of this threat. I am also aware that there is very little prospect of this situation improving in the short term.
The first defense against this infringement is to design lighting products that are not amenable to reproduction. This is not easily done, but briefly it would involve design elements that do not lend themselves to simple stamping and extrusion operations, key elements of off-shore manufacturing. This has another benefit in producing designs with more intrinsically interesting form and character. Subtle asymmetry and surface texture are elements not easily reproduced and add interest in their settings. The second defense is to keep designing. Knockoffs take time and effort, and new designs keep you ahead of the pack.