Any seeker aspiring to reach the pinnacle of strength would, when faced with anything—even the cultivation insights left by a True Immortal—seek to integrate them into themselves, rather than replicate them verbatim.
Whether ancient times were inferior to the present, or the present not as good as ancient times, is an eternally debated question that forever lacks a definitive answer.
Wu Shijiu, now in possession of the Witch Deity Teaching's latest methods and having received the most ancient inheritance of the Witch Deity lineage from the nascent Heavenly Court, has arguably received the most complete legacy of the Witch Deity Teaching.
In his view, the debate over the superiority of ancient or modern teachings is utterly meaningless; only what is one's own can be the strongest.
"I inscribe the Six Classics, and the Six Classics inscribe me."
This is something every powerhouse does when they reach the summit.