1. Dow Jones was 28,000 in the late Feb and 29,000 was justified by the P/E of 10 years at that time.
2. Dow decreased by more than 20% in March while a15% down could be more logic considering P/E of 20 and 1-2 years' earning loss caused by pandemic.
3. Dow was pulled back because Government stimulus and the shifting of demand to technology sectors completely offset the estimated earning loss in the early pandemic.
4. -10% volatility around 29,000 Dow (26,000-29,000) follows the changes in the uncertainty of containing pandemic in 1-2 years (-10% for every extra year).

More stimulus?
Reduced earning loss means smaller volatility(27,000-29,000)
Vaccine sooner?
Reduced loss means smaller volatility(28,000-29,000)
Too much government debts?
No worries for short term and we have many ways to pay that off in long term.
US treasure securities on fed's balance doubled?
Compared with the whole wealth in the country, a coupe of trillions is surely a very very small fraction. If we have to face inflated price, tech sectors' stakes will be the best place to maintain value of cash.
Election?
If it is the last day of the world, who cares about money any more?