Hindsight post incoming.
I feel like a lot of people, the DNC, other hopeful candiates and voters, were told to clear the runway and just "let" Clinton be the nominee. Essentially everyone felt like it was her "turn" after losing to Obama in 2008. This was evident in the primary. Yes, she got the most votes fair and square, but she had no real competition early on. Bernie got more traction as the primary went on and made it a real fight. But millions of voters didn't really know Bernie that well, and Clinton had been propped up as "the one", for years, so she won. Also, super delegates pretty much all threw their weight behind her. And the media. All in all, in was like a coronation.
But along the way, there were so many warning signs that she wasn't the one. The fact the Democratic primary was closer than the GOP and went on until the very end. The fact that there were protests at the convention, people booing the mere mention of her name. The DWS emails that show the DNC was against Bernie from the jump. The fact Bernie clearly had the enthusiasm on his side the entire time - bigger crowds, a clear message, and no baggage.. The fact she lost Michigan primary by surprise. The fact she lost 8 years earlier to a senator who came out of nowhere - that should have told her something. The fact she did worse than Bernie or even Biden against GOP candidates in polls. The fact she never gave a good answer on many controversial issues - emails, Wall street speeches, Clinton Foundation. The fact she never really had a clear message. I watched a lot of her rallies. It was just a long list of policy and attacking Trump. No theme. The fact that she's just not inspiring. The fact that she focused too much attention taking Trump down and not reshaping herself. The fact she LOST to DONALD TRUMP. LOL. Can't believe it. I supported her, I voted for her (but voted Bernie in the primary), I donated to her, I got in line like many other Bernie people were told to do. Never complained when it became evident she would win the nomination. And she blew it. Her campaign staff needs to take all the blame they can take.
I could go on and on. I hope this is a lesson learned for the DNC going forward, and anyone who decides to run in 2020.