They won't be able to keep saving it. At some point the USD will reach the point of no return when people actually wake up and start dumping it to buy goods, metals, crypto, whatever they can just to get rid of the dollar. At this point it will be too late for you to do anything if you are still a dolar holder at that point. Market crashes come suddenly and hit fast. One day it's all fine the next it's people standing in lines in front of their banks, and all ATMs are empty. You wake up, watch the news, and it's all in chaos.
It won't be people that trigger it, it will be countries or banks, the US owes so much in debt to many countries, mostly they're just allowed to renew it for some more time and pay a fee but if this starts to change then the US will have to print more money just to pay their debts and hyper-inflation will ensue.