The one thing that NDAs do extremely well, and the reason that companies like them signed is protect against prior art (the opposite of what we're talking about

The one thing that NDAs do extremely well, and the reason that companies like them signed is protect against prior art (the opposite of what we're talking about above). Without an NDA, if you've had a conversation with another company about your tech, then it has become public domain and you can be prevented from patenting. With NDA that problem doesn't exist.