“Yet prices keep going up and inflation remains low” <- this is logically impossible.

Also, fiat currencies can fluctuate against each other and still go down as a group. The Dollar can get “stronger” by losing value slower than other currencies. From a straight-forward point of view, wealth is denominated in dollars. But in reality, it’s denominated in value, in good things you can buy.

By this definion, we’re all richer than Crassus in some ways, affording things like global connectivity and vaccines with ease. In land, gold, and influence old Crassus was still in a league of his own, however.