In practice, ads are there because sponsors are ready to pay for something good that consumers have no desire to pay for.
Thank you, advertisers, for paying for Gmail and all those good products.
Thank you, advertisers, for paying for Gmail and all those good products.
Are you not convinced that Google Search, DDG, Gmail, Facebook, WhatsApp, Snapchat are all "good" products in the eye of many people? As far as I can tell, all of those products are paid for by sponsors.
Indeed, networks effects may sometimes be relevant to some of these tools. But that's certainly not always true.