You can also get amazing images with a point-and-shoot too (search on FLickr for images with an RX100, for example).

Again, he is not recommending you to buy an expensive lens. He's just saying you can find great point-and-shoot cameras or mirrorless with good optics for far less money or get better lenses if you jump to a body+custom lens scenario.

He's just advising not to end up in the middle, which I don't think it's a terrible advice. After using kit lenses for a while I'm giving the same advice now most of the time.