Well, I think there are three things to consider here, which explain how Amazon does so well despite having made some questionable UI/UX decisions in the past.

Well, I think there are three things to consider here, which explain how Amazon does so well despite having made some questionable UI/UX decisions in the past. 1. Most of the changes/extra features were added piecemeal over the decades, with the basic site look not really changing all that much in the meantime. So a lot of the awkward/poorly thought out/non integrated features are there because that's where it was practical to add them. 2. Obviously it's a large brand, so people are more forgiving of the design issues compared to a lesser known competitor. That's why copying the market leader may not always be the best idea, since the leader can do a lot of questionable things/make a lot of questionable design/content/whatever decisions and still have millions of people using their services, whereas a small company/site with these frustrations will just go ignored/unused. 3. They A/B test everything, and what the data says is most effective is not always what a designer would think looks/feels best. Look at some of the best performing landing pages; many look outright hideous yet convert really well.