> Do we really think that Amazon doesn't have the talent and ability to tweak their models and do A/B testing to see what provides the highest return? A/B test

> Do we really think that Amazon doesn't have the talent and ability to tweak their models and do A/B testing to see what provides the highest return? A/B testing a bad model does nothing. I'm sure Amazon's recommendations are the "best they've got" given their tech. Which sucks. Google runs a massive recommendation system at scale: their ad placement product (in Search and elsewhere). Google's recommendation tech is astoundingly better than the equivalent at Amazon, rapidly putting the most profitable ads in front of the best potential customers. That said, Google will never release their ad tech recommendation system "as a service", since it would kill their golden goose. That whole part of their company is a black hole of information.