Biden (and his handlers) was not be so idiotic as to give Mrs. Clinton the VP slot. That would be an excellent lesson in depressing black male turnout, and repulsing a handful of Pennsylvania blue dog Democrat types who jave no use for Mrs. Clinton but don’t mind Biden.
Also, Biden is old, and slipping. Mrs. Clinton is older than her years and has been slipping for some time. Biden HAS to go for someone at least a decade younger.
It was kinda a tongue in cheek statement as a “What if” - can you imagine what would happen to the country if they did gain the WH together?