I'm not quite sure that Hillary would have lost to a more "traditional" candidate --- Trump simply sucked all the oxygen out of the room, making it impossible for Clinton to get out any message other than "He's insane". Kasich and Rubio would have been constrained by facts, and facts are Hillary's strong suit.
It's been 40+ years since the GOP had the potential to control all three branches of our government. Despite Clinton's winning the popular vote, the control is swinging firmly to red states. Hopefully the Dems can re-group and re-center their focus to regain some of their political influence. By the same token, the current iteration of the GOP isn't what is used to be, so I pray that the moderates can find their way as well.
No, the Democratic Party establishment is not over because, despite the controversy, they still nominated a supremely qualified candidate. Contrarily, the GOP chose one that has no experience in public service nor knowledge on how the government works. Despite the recent loss, I believe that the Democratic Party will grow stronger as people fight to overcome the future damage that may be done.
The democratic party establishment is not over. It is wrong to say that since they remain to be the opposition party. If a political party fails to win an election does not mean that it is over, they have a chance to run for elections in the coming years too.