Those are external and out of sight and out of mind. It doesn't affect the average American.

This is very different. It affects Americans and deaths are happening everyday. Cases in the south are going up. Florida, Arizona, and Texas are reporting the highest amount of cases since the pandemic. 2 of the biggest economic engine states (Texas and California) are on the cusp of closing again. Stores that opened are now closing again. People can't go to their favorite stores, people have lost their jobs, once the federal aid runs out and the FED doesn't want to / can't pump the market anymore, shit's going to hit the fan. There's also a fear of a 2nd wave when the weather gets colder and that's right before election time.

You are right that there's a rally around the flag effect in disasters and gives a boost to approval rating. But a sustained disaster and very little is done to fix it is not going to help his approval rating.

You can deflect some blame to China but it doesn't answer why the US has one of the highest cases in the world. China doesn't have jurisdiction on US soil. People having coronavirus parties, no respect for social distancing or masks (some security guard got killed for asking someone to wear a mask at the dollar store), protesters, people feel like they have to work or lose benefits which spreads the virus, high healthcare costs, etc.

If you're talking about wild fires, hurricanes, wars that take place outside of the US, most Americans don't care. It doesn't affect them. This is totally different. It affects the people they know / love, their own health, and their jobs. Every single American today is affected by this and the longer it drags out, the worse it is for leaders in office today.