Gmail (and similar products) killed it.
The internet made it possible for a company to serve hundreds of millions of people without the overhead of listening to, or supporting, or giving much of a shit about them. "Why are you complaining? It's free!"
Gmail envy makes it seem like you're some underachieving sucker if you bend over backwards to deliver a great customer experience.
It probably would be possible to have a billion customers and make them happy, but the number of employees it would take would only make you rich, instead of unfathomably rich.