US will one day be in hyperinflation as you said no currency will be reserve currency forever. However when that will occur is a big unknown. I would want to add in stock market over the past two decades since the dot com bubble it has been the tech sector that has sustain the best bull rallies out of all sectors. This is because as technology make goods and services cheaper it leads to a form of deflation. Investing in tech is deflationary. However as of now the FANG+MSFT stocks are off their all time highs while Nasdaq is weakest among all sectors. This is only short term but it will be interesting to watch if tech stocks do go lower from here as this is a signal that inflation is on the horizon.