PJ, using your line of reasoning. Then whoever created all that whole lot of DGSD arts automatically become greater geniuses then the Greats?
One can claim that the Xiao Yao elders, DY and especially XZ benefitted from pre-existing martial arts which were more powerful then the Greats. Can also include JMZ since he had access to XWXG.
MRB is debatable. Was his Star shifter and Canghe Finger equal to the Greats martial arts?
XYS and XF. They had nothing better then the Greats. And the argument from the GJ supporters is that XF has access to less techniques then GJ.
Special mention for TSTL. She started learning that crazy skill at her pre-teen years. A skill so powerful that experienced martial artists in their middle ages can fire-deviate and die from just by looking at its first stance. Would the LOCH Greats and GJ/YG be able to learn Ba Hwang Liu He Shen Gong when they were 8 yrs old without suffering fire deviation?