Hillary never lead by 20 points. Her biggest lead was by 7.1 points on 18 Oct. Although she maintained the lead from 1 Aug on. Trump narrowed that lead from 7.1 to 1.9 points on 1 Nov which Hillary finally won the popular vote by 2.1%.
But I do agree, it is far from over. On 25 July 2016 Hillary had an 0.4 of a point lead in the polls vs. Biden's 8.7. Since 1952 only one presidential candidate with a lead of more than 6 points at the end of July has lost. Micheal Dukakis in 1988. Now if you go back 4 more years to 1948, that is then 2 presidential candidates with Thomas Dewey joining Dukakis. Dewey had an 11 point lead over Truman at the end of July, Dukakis an amazing 17 point lead over Bush. So it can happen. But polling was in its infancy back in 1948, more tuned in in 1988. historical polling only goes back to 1936, so you have 2 since then. Dukakis continued to fall, at the end of August his lead was 7 points, at the end of September Bush had taken a 5 point lead, expanded it to 10 points at the end of October before winning by 8.
If I were a democrat, I'd be feeling pretty good right about now. Biden leads in Arizona, Michigan, Wisconsin, Pennsylvania, Florida, North Carolina, Iowa. Is within one point in Texas and Georgia of all places. All states Trump won in 2016.
But all it takes is one unforeseen event, happening to upset the apple cart, to turn an election on its ear. The thing is Trump was always within easy striking distance. 5 points or less most of the campaign. Within 5 points means the race is very competitive.
It's high past time that we start electing Americans to congress and the presidency who put America first instead of their political party. For way too long we have been electing Republicans and Democrats who happen to be Americans instead of Americans who happen to be Republicans and Democrats.