Just because they are registered Democrats, it doesn’t mean they are voting for Biden. A big percentage of the most enthusiatic people attending Trump rallies were Democrats.
And conversely, just because they’re Republicans doesn’t mean they are voting for Trump. But I do suspect that there are far more ‘walkaway’ Democrats than ‘never-Trump’ Republicans.
You asked if anyone had heard of the betting odds of Trump vs Biden. I sent you some. You must have not seen them because I haven’t heard from you.
I’m a registered Democrat, for various reasons.