It's not that they are bad at their jobs. It is more about their job description cannot deliver what it promises.

I have just published my own "Polls are Wrong" article.

https://medium.com/free-factor/the-presidential-polls-are-wrong-76edb7c709c9

In that article, I link to my experience of being an interviewee of a pollster.

I believe the polling companies are still struggling with finding a random sample when most of us switched away from land lines.