Ethereum isn't a company that sells a product. It's a network made by Vitalik and with his other co founders.
The same as the other projects, they have dedicated amount of Ethereum to themselves and that's how they've made money from it. When they've raised the value of it then the Eth's that they've held.
I was just going to say that before I decided to go through the comments to see whether someone has said it or not, and here it is. This is how the founding members of a cryptocurrency usually make their own money from it. When they create the cryptocurrency they mine to an amount that they are okay with and then they store it in their wallet and when the project becomes a success and the value increases, they make their money.
It’s just like Satoshi Nakamoto that owns an address with around one million bitcoins. That’s worth billions of dollars at the current rate. So assuming he decides to withdraw it, which most of the other crypto founders has done, that’s how he’s going to make his own money.
