Given that the primaries are over half a year away, I might bring your attention to predictions that other people made this far out before the 2006 elections. There is no such thing as a "lock" in politics.
That may be true, and you make a very valid point, however, I have a strong feeling that this Democratic race is different from any in history. I believe it will be over before too long into the process.
You should read my generic predictions:
https://uselectionatlas.org/FORUM/index.php?topic=54364.0During every single election cycle, there are people who make bold predictions, and then when critics point out past elections when everyone's predictions turned out wrong, the predictor will respond by saying "Yeah, but this time is different." Every single time, there are people who say that. But the incorrect predictions keep on coming.