Short answer: “Persuade 500 people to pay you $2 a month for an essential service.”
Longer answer: “Be a good seller who can help people see the advantages of using an @godspost.com email address for a mere $25 a year. But before that, you would need to buy the service, site, and domain from me. And you would also need to pay out $84 a month for the service to power the service. ”
So…why am I not earning at least $561.09 a month via this great service? I am not a good seller nor a good persuader. So I haven’t been able to get even 10 people paying $25 a year for this service.
And I probably won’t persuade you to buy the service, site, and domain from me. (But I’ve been wrong before.)
Of course, you could forget the whole pursuit of filthy lucre and “unseemly capitalist profit” and offer the service for free. (But I really can’t offer it to you on that basis.)