The empty space of the website

When you browse a website. Do you ever find many web have empty space for the both sides like this?

But there are still some website don't leave empty space like amazon.

The webistes like amazon are very few.But why?
There are many reasons, but the main ones are visual cluttering and hierarchy of information on one side, and structural consistency on the UI Design.
On the other hand, as a  ux designer speaking for the sites I've made: we didn't design for large width display. The costs of designing and developing a responsive and scalable website across desktop and mobile are already quite high. Our analytics show that 90%+ of our users view our site in <1400 px wide resolution.
At the end of the day, it's not worth it to spend the time and money designing and implementing for the <10% of users who browse our sites at >1400px wide resolution.
finally,normally the readable area of a paragraph should be no wider than an average sized hand.