"What is a "likely voter" today? "

Exactly.

Besides, these polling groups use the same database over and over, regardless of how demographics or voter sentiment changes.

It is very difficult to beat a sitting president. We know that from Hussein's reign, among others, despite the dismal state he steered the country to.

"It's the economy, stupid". If the economy remains strong Trump gets reelected. If we have a recession -- and there are hints that could happen -- then whatever cartoon character the Democrats pick will win.

Me dino recalls the slanted polls of 2016 pretty well repeating, "Rejoice! Clinton gonna win! Rejoice! Clinton gonna win! Rejoice! Clinton gonna to win!" with all that ballyhoo leading to~~https://www.youtube.com/watch?v=wDYNV...

Well, his campaign manager makes a good point, polling science has not kept up with reality. People get their information from a lot of sources and a statistical sample of people who get their information from the wide variety of sources would have to be much larger to be meaningful. They use phones and a sample size of 5 or 6 hundred, and it's just not accurate. What is a "likely voter" today?

The latest poll I saw shows Trump at 49% approval. so not taking the other polls seriously may be justified. Given the track record of polling organizations in the last election I would say skepticism of the part of the campaign could be warrented.
As I have commented in prior posts and comments.most of the polls as don't provide enough information on sample size and composition and error bounds to make a truelly accurate assessment of the results . I did a little diging on several of the polls and found the candidates where within the margin of error of the pols. not surprising at this stage on the game.
I just wish the pollsters would provide all of the data and the "News reporters would provide them to the public. I'll probabily be long gone before that happens on a regular basis.