Of course evidence would be much better (though I'm not sure what kind of evidence I would actually trust). But if the story is true, it makes sense that we're not seeing anything: given that they're talking about an arms race with other countries, the US would not want to show any details that adversaries might not already know. Since the US government looked over everything they wouldn't allow actual evidence to be released.

I'm not saying this is true or false, but if it's true, we'd expect no actual evidence.