If I recall correctly, 60 Minutes ran a segment on this earlier in the year.
Using AI, they can continually improve the algorithm so that you would possibly only need 15-30 minutes of recordings to create something that the ear couldn't distinguish as fake. Using AI analysis, though, you could debunk fakes. They're working on that as well.
As to biometrics, those can easily be bypasses in the right circumstances (seen that in the movies a good bit).
Since all social media seems to have turned into a swirling cess pool of misinformation, stupidity, bigotry and outright lies, only the weak-minded use it for any serious information.
The only way to clean this mess up is to rescind the law that indemnifies them from any liability for the content published on their sites.
People seem to have forgotten or never known that lobbying groups in the US were started as a way for small, grass roots organizations to compete for access to politicians. You can see how that's worked.