Not paid directly - it's a combination of 1) brands being top of mind 2) what people / robots will recognize and ever so likely potentially to share or what will have the tiniest bit of extra SEO juice.

#1 only comes from a lot of ongoing PR outreach, coffee chats, briefings, etc - which takes time and $$$$ usually via an agency working nonstop on developing relationships to keep a brand top of mind for side mentions like this and to be at the top of the rolodex when a reporter needs a quote or some help understanding an industry or technology space.