Just wanted to throw down some fun numbers so everyone is aware of the truly incredible job our President did in this election.
In the history of our Republic, there have been 20 incumbent elections where the incumbent was re-elected (I'm including 2020 and Cleveland's second election after one term of Harrison, but excluding VPs turned Ps who were not elected themselves for their "first term" as President, sorry Teddy).
In each incumbent election, the general rule is that votes for the incumbent increase, while voter turnout decreases. Votes increasing for the candidate can be the result of a lot of things - population and demographic changes, changes in who is allowed to vote in between election cycles, general approval rate increase, etc. Furthermore, as a general rule, voter turnout usually decreases in these elections, as less people vote in incumbent races. This general rule has held true for 10 of our 20 incumbent elections where the incumbent was successful in seeking re-election.
It is possible for a candidate's vote total to decrease between election cycles, while turnout increases, and this did happen in Roosevelt's 1940 election, but it is much less likely than the general rule, as it most likely means that the voters are enthusiastically moving to the opposition, and therefore the incumbent is much less likely to be re-elected.
What should happen only once in a blue moon is a decrease in voter turnout and in overall votes, that still nets a win for the incumbent. Although these two factors correlate somewhat, a decrease in votes and turnout would seem to indicate a loss of goodwill and a drop in enthusiasm among one's base. This occurred three times, in Roosevelt's 1944 bid, where he faced criticism for seeking a fourth term, and in Obama's 2012 bid, where he lost many of his record-breaking 2008 voters due to policy missteps and general voter apathy. It also occurred in Washington's 1792 run, but Washington ran unopposed, so it's a bit of a special case.
Then, finally, there are those elections which see both an increase in votes, and an increase in turnout. I could say what I believe this is indicative of, but a quick survey of all the years where this phenomenon occurred will make the trend clear. 1812, 1916, 1936, 1984, 2004. These were all elections concerning grave times for the nation - The War of 1812, US Entry into WW1, The Great Depression and the rumblings of WW2, and the Post-9/11 and Iraq War Era. The exception to this rule is Reagan's '84 bid, but we can chalk that up, I think, to Reagan's widespread popular appeal and charisma. The only war that doesn't fit with this trend is the Civil War, where Lincoln's re-election followed the general rule, but that can be chalked up, I think, to Lincoln's controversial wielding of the executive power in his time.
2020 was another one of these moments, with an increase in voter turnout as well as overall votes for the incumbent. I've included my spreadsheet, so you can all take a look at the numbers for yourselves, and see how they stack up. I just wanted to point out, however, that in the 2020 Election, voter turnout increased 6.6%, the largest in history for an incumbent election, a full percentage point more than the turnout between 2000 and 2004 in the post-9/11 era, and that Donald Trump in this election (only referring to the "official count", whereas Trump won many more millions of votes) had an incumbent vote increase of 117%, comparable to Bush's 123% and Reagan's 124%.
Thought y'all might enjoy some number-crunching. Hold the line, pedes, and stay resolute!
TL;DR: According to history, Trump did freakin' AWESOME in this election.