PS: This chapter is a bonus update in appreciation of a fan, Lin Luo Xun, who donated ten thousand Qidian coins.
The Su Family has lived in seclusion at Ningyuan Hall for nearly ten thousand years. For them, the hierarchy within Ningyuan Hall was never determined by strength, but by bloodline.
Only those of the direct lineage had the right to compare themselves with others of the direct lineage. As for those of the collateral lineage, even if you've reached the Divinity Transformation Realm, you're still inferior to a direct descendant in the Postnatal Realm.
This wasn't originally an issue, and even the collateral-disciples of the Su Family had grown used to it. After all these years, they too had developed a certain impression that they were of the collateral-bloodline and couldn't compare with direct disciples. Therefore, they naturally fell short.