> Sure, we can't, but if you open source it, you'll make strictly less money than if you hadn't (because if nobody was going to buy it, they aren't going to pay you money if you open source it anyway).

That isnt correct, a lot of people buy open source software specifically because it is open source.

Not entirely true. You can monetize around the open source software you built but this largely depends on what you built. In this case, she is expecting to raise 30k for a feed reader, when there are already open sourced readers with a similar functionality(?).

You might make more money by open sourcing: if, for example, it's not currently in a state to have anyone be willing to purchase it.