I'll be honest, I completely forgot that the RX 400 series cards were still GCN.
I think the Vega cards were the final evolution of GCN? I got lost with all the different version revisions by the time the R9 Fury series released.
Regarding the TFLOPS comparison between the RX 480 and One X GPU, it can be used to get a rough idea of how the One X GPU compares to desktop counterparts. It won't be an apples to apples comparison due to different clocks, CU counts, etc., but it's something.
I'm not talking about selling consoles, I'm talking about how we can't use TFLOPS as a performance metric when comparing two generations of consoles with two generations of GPU architectures.