My guess is it's also down to the proliferation of cross-platform UX toolkits that allow for A/B testing of every single component. Making a cool UX thing that

My guess is it's also down to the proliferation of cross-platform UX toolkits that allow for A/B testing of every single component. Making a cool UX thing that requires native OS features would go against that philosophy. And, as you say, it's not a revenue driver so nobody will be fighting for it.