What if USD loses it global reserve status?

2 questions I'm curious for opinions!

1. What are the chances USD loses global reserve status within the next 10, 20, 30 years

2. If USD did lose its status, would the returns of indices like the S&P 500 and US Total Market be similar compared to the past or would they suffer?

Main reason I'm asking is because I've been investing for a while and 2 of my main holdings are VOO and VTI. It would suck to have those suffer after years of investing within them.

Would the American economy suffer to the point where the S&P will never have an average annual return of 10% with dividends reinvested again?

Thanks guys