1 satoshi can absolutely equal $1 in the future. this will signify a collapse of a fiat currency which has happened many times. The US dollar is not immune. Politics and banker greed causes it.

The real question is will 1 satoshi ever be too valuable to be practical as the smallest unit of bitcoin. If that does happen there is nothing in the bitcon whitepaper to say you can't add more decimal places. Maybe in te future we will need 100ths of a satoshi. That iwould be easy to do

I'm quite suprised noone mentioned this already