Also consider what would happen should the automation making all this possible fail. It becomes a very busy flight deck at that point - probably a little much for one guy to handle.
A second pilot also provides a check and balance for the decision making process. An FO saying "what the heck are you doing" at least makes the captain stop and think about what he's about to do. Also, CVR's become kinda useless in determining accident causes - unless the guy talks to himself.
Even embraer says that this is just a concept at this point, and faces pretty serious challenges - not just from a technical perspective, but from a regulatory and public perception stance too. And at best, the prototyep is 10-15 years away.
So I wouldn't lose too much sleep over it just yet. I will probably happen some day, but I don't think I my lifetime.