Actually disco peaked out in the late '70s and was dead by the '80s. So it looks like disco and Skynard flourished at the same time.
Yeah, new wave killed disco, not rock. Straight up rock bands had a hard time in the late 70s early 80s. Led Zep disbanded after Bonham’s death, Aerosmith all but disbanded until they did that remake of Walk This Way with Run DMC, Alman Bros disbanded in 79. I could go on.