I hope I clarified that there are legitimate historical questions, at least if the data were available.
But a straight monetary conversion isn’t one of them.
We should become uncomfortable with price comparisons fairly quickly. With a modern economy, 10 or 20 years out will lead to the furrowing of my brow. But at least the geometry is going to mostly line up. It’s recognizably the same world, not yet another planet. 50 years will have me shaking my head, and 100 years is right out. The distortions build up over time until nothing sensible is left. There are economists who find even year-to-year comparisons somewhat distasteful, and while I don’t go that far (and would guess the majority of economists don’t either), their discomfort has a solid basis. Inflation is a tricky thing, much more so than people realize.
If you still think a probabilistic range might be helpful, then I’d be negligent to not mention the Measuring Worth website. That doesn’t answer the OP’s question about Rome but it does give another perspective on how hard the question is.
You can go to the “Relative Values US $” in the left sidebar, then in the open fields put in, for example, 1 dollar starting at 1800 for an initial year and compare to 2014. You’ll get a “range” of sorts, one whose upper bound is more than three orders of magnitude larger than the lower bound, based on different ways of comparing over time. But I would say, again, that the range itself isn’t useful or meaningful. What can be useful is the nature of the individual subquestions. The CPI comparison is trash, but some of the others are interesting information. They work because they narrow the scope of the question, and in so doing provide a deeper idea than just a basic currency conversion over time.
But of course, that website provides figures for modern countries. Data for ancient Rome’s interesting subquestions is going to be much tougher to come by.