Well, I think Apple and Google does not sell directly your data to others, that would be like handing out the Coca-Cola recipe, that would undercut their advantage(your data is their gold). They sell, let me call it "advertisement slots" that is based on your data or create new anticompetitive products.I did one single Google search to see what would come up. I took only one single result, the first one that came up. I was just curious if data was sold or not. And the result:
NHS sells data
So I am afraid that data selling is a common practise even by the British NHS
The thing is, with Google we always knew what they do, and we were able to be careful, but with Apple that's a huge breach of trust, specially after all these bold privacy campaigns that ran over many years fooling their customers.