Boy oh boy, this is all we talk about anymore. Always specifically in the language of unicorns too. People seem to have really latched on to that.
The press and HN/etc DOES talk a ton about unicorns. It's the only grade that has its own name. There's no word for a $10-25m startup, or a $100-500m startup. No, only $1B-unicorns. They have their own name and we're obsessed with them. This either highlights or promotes the notion that investors (and entrepreneurs?) are only interested in billion-dollar companies.