Why don't popular sites like CNN, bbc and arstechnica use HTTPS?

I am developing a new website that won't have sensitive data transfer at least on the short term (like logins or money transactions), Google says every new website should use https or will be punished on the long term. Mozilla seems on the same track. So why don't many MANY popular websites use https? Of course, they have the money and infrastructure to do so. Is there something hidden in this issue?