Phone books existed long before the internet.

I feel old writing this, but once a upon a time, phone-book companies (often the phone company, but not always) would deliver a phone book to every address with a phone. This was paid for almost-entirely by the advertising sold by the phone-book company.

If a company or person wasn't in the phone book, they pretty much didn't exist.

All of this has happened before, all of it will happen again.