The myth will never die. Plastics that use soy degrade no faster than petroleum based plastics, and do not attract rodents to a greater extent either. Rodents love to chew on all wires, including petroleum-based ones.
Not sure what the point of your question is, though.
Meanwhile with the exception of wires in high-temperature areas, PVC just doesn't do that.
Aside from that ... this is not an anecdote vs anecdote debate, these wires have been around for decades and this exact question has been studied scientifically. The degradation rate and wire-chewing prevalence are comparable with PVC.