I don't think that search engines care about the few letters at the end of your domain name, they are more concerned with the actual content of your page.
Supply and demand. If businesses want these TLDs enough, they will pay for them, therefore people will charge for them.
They are at the end of the day just a collection of letters. But many of these new ones have meanings relevant to various types of site or businesses. So they are really just a way to have a domain that looks good or is catchy and easy for people to remember as well as being descriptive about the nature of their business.