This is an interesting strategy. The only thing I can't wrap my head around is that, even if biden either bows out or gets thrown out ( 
) and replaced by the democrats, I just cannot see how people would want the country to continue the way it is going.
Because the person that replaces biden will certainly continue the on-going agenda which in my opinion will continue to drive the nation down the toilet.
And it looks like even if Trump doesn't win the GOP nomination, the democrats would still try the strategy you described.
Either way I think biden will hobble off into the sunset, with "Dr." Jill holding his arm steady and son hunter holding on to biden's britches while sucking his thumb.
When it comes to campaign
strategery, the number one objective should be picking a nominee that can win. However, we all know it takes outspending in many swing states to wn, which pushes fundraising to the top of the priority list.
In order to raise money, the dems need Biden in the picture. Anyone else, and donors might wonder about an alternate candidate. i mean, how many incumbants decided not to seek a second term for President? That's unheard of. Even Carter ran again after his dismal term was ending.
Keeping Joe for now keeps the donors donating, especially if they can keep Trump in the picture as the one to beat.
If and when Joe backs out, it'll be when the war chest is big enough to beat Trump no matter who is their nominee.
Hillary spent twice what Trump spent, so the prize doesn't always go to the richest. But what the party failed to see is how horrible a candidate she was.
Clinton was an anomaly in the spending-for-votes process. Normally resources matter a great deal, both in getting the candidate's message out, and in attacking or defending against dirty ads by opponents.
Anyway, if he bows out, it'll be over a fake health crisis -- just to avoid the appearance of switching horses in the last leg of the race. It would not surprise me if it happens after early voting begins.