What evidence does the book cite to support this premise?
Also, a plea: let's please answer this question before everybody posts their personal hot takes on children and parenting.
Alfie Kohn's book, "The myth of the spoiled child", spends a lot of time pointing out that evidence behind claims like this are not only deficient of data, but are claims that seem to be made continuously throughout history of the latest generation of children.
I was hoping to find some credibility through the interviewee's name, but her own bio states she "is an award-winning independent journalist, author and speaker". Again, this isn't inherently bad, but it boils down to her making a bunch of observations that juxtaposes her children to others.
I don't know any child that struggles to manage their behavior. Adults that I have heard complain about this seem to be experiencing some panic over not being able to control children's behavior (i.e. less screen time). And it is worth noting that perhaps they are being over-protective.