Why don't you support Bernie Sanders? (if you don't)

Crossposting from the Warren thread:

Interesting numbers that illustrate Bernie’s ceiling, which has descended considerably since March. His unfavorables are the worst and the “willing to consider” the lowest.

IOW: he’s toast. Unlike other candidates, he can’t grow his numbers. He is a known quantity, and Democratic primary voters have finally grown weary of him. His time has passed.