RTINGS: "We found that in our 20/7 Burn-in Test the red sub-pixel is the fastest to degrade, followed by blue and then green".
This statement, however, doesn’t automatically mean that red OLED material used in B6 degrades faster than green and blue in a pure (fair) experiment.
I don’t know the exact structure of this panel, but it most likely has a stack of OLED layers (of different colors to form white) and color filter layer - similarly to the modern WRGB OLED panels produced by LG Display. So, this panel doesn't have red, green and blue OLEDs as sub-pixels.
To make a relevant comparison of lifespan for OLED of different colors you have to make an experiment with the same sized diodes (or, at least, same [subpixel area / pixel area] ratio) and same brightness. I bet, in such an experiment blue OLED material from B6 panel will degrade faster than green and red.
On the other note, I’m sure that blue OLED used in the current Samsung QD-Display technology is much more stable compared to the one used in B6.