> What is wrong in the culture / education of engineering that people have to be taught this after they start working?

Whatever "customer experience" means is specific to an industry/company, not a universally agreed upon term. For Amazon, which is largely B2C, UX is critical. For other industries, delivery time may be more important. There are such things as tradeoffs, and in some cases, it makes sense to prioritize things other than an awesome UX.