I've been pondering how J.K. Rowling managed to morph from Beatrix Potter in the 1990s to Margaret Thatcher today.
Perhaps it's the toxicity of extreme wealth and fame: they isolate you from normal human interaction, so that your empathy atrophies, and you end up living alone in a narcissism bubble.
When she wrote about Voldemort's soul withering and dying at the end of the Harry Potter series, did some part of her brain already see it happening in herself?