Because that's not how things work in China. An off-brand copy would be a literal copy of the PCB with cheaper and /or missing components (especially EMC-relate

Because that's not how things work in China. An off-brand copy would be a literal copy of the PCB with cheaper and /or missing components (especially EMC-related ones). An "improvement" from a different OEM would have obvious differences in parts like the heatsinks (they are literally the same part, with extremely similar cutting marks) and various other generic interchangeable parts (e.g. the input MOV, the IEC connector, the optical feedback package on the top etc).