Call me cynical, but I firmly believe that ES6 is more useful to Bethesda as a perpetual 'carrot on a stick' than anything they would get from actually releasing it. The people that made Morrowind, Oblivion, and even Skyrim what they are no longer work at Bethesda, but the goodwill of the series remains in people's minds, and they associate that with Bethesda, even if a majority of their modern releases have been dumpster fires for one reason or another.
There's a reason we've gone almost 15 years without a mainline elder scrolls game, and I'm pretty sure it's because even Bethesda knows that they likely can't capture that magic again.
Video evidence is relatively easy to fix, you just need camera ICs to cryptographically sign their outputs. If the image/video is tampered with (or even re-encoded) the signature won't match. As the private key is (hopefully!) stored securely in the hardware IC taking the photo/video, any generated images or videos can't be signed by such a private key.