Something to consider in evaluating Trump's victory

This is a list of the United States Presidents who served two consecutive full terms and left office without dying while President. since 1800:

Thomas Jefferson
James Madison
James Monroe
Andrew Jackson
Ulysses S. Grant
Woodrow Wilson
Dwight D. Eisenhower
Ronald Reagan
Bill Clinton
George W. Bush
Barrack Obama

The first three succeeded one another and were all members of the Democratic-Republican party.  President Jackson was a Democrat and succeeded by another Democrat, Martin Van Buren.  President Grant was a Republican and succeeded by Rutherford B. Hayes, another Republican.

Then things changed.  President Wilson was a Democrat and he was succeeded by Warren G. Harding, a Republican.  Eisenhower was a Republican and it was JFK, a Democrat who succeeded him.

George H. W. Bush managed to follow in the Republican footsteps of Ronald Reagan, mostly due to the Democratic Party nominating a very weak candidate. But since then the trend of two-term presidents being succeeded by a member of the other political party has continued.

Do we get political party fatigue when it comes to the presidency?  Why is it so difficult for a Democrat to succeed a Democrat?

I wish I knew.  I find it an interesting question.