POD: 1968, after the final US tour of the Yardbirds, the band breaks up as OTL, but instead of forming a band of his own, a disillusioned Jimmy Page decides to go back to session work indefinitely instead of forming a "New Yardbirds".
What would be the impact on the emerging sound of hard rock & heavy metal?
If those styles still emerge, which bands would be at the forefront?
How would the career of OTL Led Zep members unfold in this timeline?