If you don’t want to read this whole article, the answer is no.
In fact, the polls were fairly accurate on both the state and federal levels in 2016. The trope about President Trump defying political gravity and conventional wisdom is only true to the extent that not many people expected a political novice who had never seriously campaigned for so much as dog catcher in his native Manhattan to pull this off.
However, on even the most basic examination, the notion that Trump had some secret well of support that went un-polled all along and suddenly emerged on Election Day is quite easily disproved.
One important distinction to make is that averages of recent polls tend to be more accurate than any single poll in isolation. Think of a poll as a picture and the averages as a video showing more of what happened before and after the picture was taken.
Beginning with the nationwide popular vote, which we know is not and should not be the deciding factor in presidential elections, the 2016 Real Clear Politics average  had Clinton winning by 3.2 percent and she did in fact win the popular vote by 2.1 percent.
In the final polls leading up to Election Day, Clinton was shown leading by anywhere from 1 to 4 percent, and one poll even had Trump up by 3 points nationwide. This result can hardly be pointed to as an example of inaccurate polling.
That said, the Biden campaign shouldn’t get too comfortable with their 7.5 percent lead in the RCP polling averages. On this date (August 13) in 2016, Clinton’s lead  averaged 6.4 percent.
On average, Trump was shown leading in those states prior to Election Day to some extent or another, and the results in all three of those states were not shocking to anyone who paid any amount of attention.
With those three states all shown as being somewhat close but still in Trump’s favor, the election was left in the hands of voters in Wisconsin, Michigan, and Pennsylvania. With these three states and many typical red states putting Trump at 260 electoral votes, Clinton would have to run the table in those traditionally blue states to win by a margin of 278-260. As we know, she did not. However, this again was not due to some great underdog stealth campaign by Trump in those remaining states.
The Keystone State was consistently within striking distance for the Trump campaign in the waning days of the 2016 election. The largest lead for Clinton there in the last week or so was 6 percent. One poll showed the candidates tied, and another showed Trump ahead by 1 percent. The RCP average  showed Clinton with a minuscule 2.1 percent lead, but Trump ultimately carried Pennsylvania by 0.7 percent. In fact, only about 45,000 voters made the difference in Pennsylvania.
Michigan  was also shown as being a close race toward the end, and was certainly not safe Clinton territory. In the last few days there, Clinton had an average lead of 3.6 percent, with the last polls showing her up by 4 or 5 points. The final Michigan poll showed Trump with a lead of 2 percent among likely voters, and he took Michigan by a nose at 0.3 percent (or a little over 11,000 votes).
This brings us to the one and only state on the entire map that could accurately be described as a surprise, as a total “What the [redacted] just happened?” state: Wisconsin.
Every poll in Wisconsin dating back to August of 2016 showed Clinton ahead by enough to consider Wisconsin safe, and she held a six-and-a-half point lead  on average. Ultimately, Trump won Wisconsin  by less than 1 percent.
For those keeping score at home, that slim margin of victory was thanks to a mere 22,748 votes. By contrast, President Obama won Wisconsin  by nearly 200,000 votes in 2012, a year that saw higher turnout in the state than in 2016.
2020 Battleground States
For what it’s worth at this point in time in the bizarre 2020 election, Biden is shown ahead on average (and, importantly, among likely voters) in Pennsylvania , Florida , Michigan  (where the Trump campaign has gone off the air  and seemingly given up already), and Wisconsin .
Of course, the conventions that usually give candidates a bump in the polls have yet to occur, and will be dramatically different this time around. In short, the Biden campaign shouldn’t get comfortable, and the Trump campaign shouldn’t panic. Yet.