Because thats when the last Presidential election was and polls were wrong. You brought up polls and 2018. Which have 0 change on Trump.
You think those "Dem" voters are showing up 4 years later, when they didnt show up to win the Senate? You think people magically smartened up and arent falling for fake Facebook ads and onion articles? Same dumb people voting for the same interests against themselves.
Read the thread of evidence outside your group of like minded people.
People dont care enough to educate themselves on what impeachment actually means or what Trump actually did. These people think collusion is illegal. These people think the Mueller Report exonerated Trump because Republican news is louder than the facts.
You expect them to vote for Biden, the guy tied into impeachment because Republicans made it the narrative?
Come back to reality. It aint happening if Biden is the nominee
You're the one that needs to come back to reality here.
They didn't win the Senate this year because the seats that were up for re-election in the Senate were in states that heavily shifted red and was the worst map for the Dems in years. The entire House was up for re-election all over the country.
The fact of the matter is there are more Dem voters than Trump voters because Dems outnumbered them by showing up in 2018! Not just in 2018, in all sorts of special elections in districts where Trump won by crazy numbers. Just because Trump wasn't on the ballot doesn't mean Trump supporters weren't energized to vote then!
Currently, Biden is beating Trump by around 6 or 7 points as of now, including in swing states. Things may change and his support may drop sure, he might not even be the nominee! But as of now if Biden is, it's not looking good for Trump!
No data shows that things are currently good for Trump. His support has always been the same, terrible level since his presidency started.