Under an NDA you might be allowed to download bulk data and use it to see if you can get further into the system.

Companies respond in different ways to disclosures, by independent researchers and by people under contract. You are absolutely right that in many cases the findings end up in a drawer. This is a real pity. Invariably those will sooner or later be exploited by the bad guys and then the company has a serious problem: they will have to show their homework and if it is found that - at least in Europe - they were aware of the issue but did not take action it may well have the effect of changing a warning into a fine and a fine into a larger one.