You were right about Trump, but you're very wrong here.
All five of the people you listed above have virtually no shot at winning the nomination.
We are getting close to November. Even in the pre-social-media days of Presidential election, it was very uncommon for a candidate polling in the single digits on November 1 to win the nomination.
Nowadays, it's really difficult, because we are exposed to so much more information than we used to be. If you aren't jumping out to the top few spots early, you're screwed. In the past, sometimes a candidate could rocket up into relevance late, because we didn't have enough exposure to them (or the other candidates, for that matter).
Trump actually proved that in 2015/2016. For a long time, people were dismissing his early lead as just gimmickry, and assumed that he would wear out his welcome and a "real" candidate would take over. Even I fell into that trap. But it didn't happen. Trump proved that early momentum in the primary process is huge (as is constant exposure, which he got for free from the mainstream media which WANTED him to be the one facing Hillary... oops!)
It's a 3-person race.
Biden
Warren
Sanders
For the reasons stated in my post, I think Sanders is already a longshot at this point.
Biden +500 is yuuuuuuuuge value.