A friend is someone who'd rather spend his time with you than anything else. In the past, there really wasn't any other outlet to spend your time. Now, it's a valuable commodity targeted with precision and monetized by companies. By putting a price tag on time, you have millions of dollars spent trying to take it from you, and you can't get that time back.
Who do you think would win, some relatively pleasant person who wants quality time, or the latest million dollar attention grabber? That's why there are no friends beyond coworkers now.