Why did HIllary Clinton lose to Trump in 2016?

The real reason is history. It's all about the history of the United States.

First of all, study election patterns for the last 200 years time. No president of either party has EVER been successful mostly running a third term for that party as president:

Except Franklin Delano Roosevelt who was elected to 3 term because of World War II. So, that meant that his vice President Harry Truman was the 4th Term of a Democrat since 1932.

The 2nd time ANY president had 3 terms of the same party was Bush I in 1988 after Reagan. So, that meant that 3 terms of a Republican President from 1980 until 1992. Then two terms of Democrat Bill Clinton, then two terms of Republican Bush II. Then two terms of Democrat Obama.

So, there was likely little to no way that any man could have won who was a Democrat as president of the United States when you study history anyway let alone any woman.

And then how many female presidents have you seen in the U.S.?

So, given history there was no historical way for Hillary to EVER have become President unless it was the next election after Bush and THEN instead of a woman winning a black man, Obama won instead.

So, that was the only real election (historically speaking) that she could have won and OBAMA took it instead then.

So, historically speaking it was a Republican's turn for one to win given history so far here in the U.S. and demographics being what they were.

So, even though there are less and less Republicans being born every year compared to Democrats so many new Republicans who have never voted ever before wanted to completely shake up the system with a populist Republican that we now have Trump in place.

Is this a good thing or a bad thing?

Ask me in 4 to 8 years.

Because it is definitely the strangest thing I have ever seen happen to the United States and I saw personally the Cuban Missile Crisis, the Kennedy (two of them)being assassinated along with Martin luther King, then 9-11 and everything else along the way. And I've got to say Trump is even stranger than the Viet Nam War in his own way.

And the Viet Nam war was about as popular as a lead balloon as all our boys died as we watched them struck down often on TV and put into body bags before our eyes every night on the news then. And then we watched them come back to the U.S. on planes with Flag draped coffins.

Trump is about as popular as the Viet Nam war was (in other words he is the least popular president at this point 'at almost 100 days' in U.S. history).