Hmm. I wonder. While I'm sure your math is correct, there are differences outside of the paper itself. For example, we're not going to the general store and buying pieces of paper one at a time from the merchant.
"I'll have 17 pieces good sir"
We can order bulk from Amazon in the form of a package of 500 sheets for $10, but that paper is also higher and lower quality than the paper from 200 years ago. (Thinner, for one thing..).
Of course, buying 500 sheets is part of the whole change in our economy. Mass production enables part of that. It seems, to me, so very hard to equate wage to purchase this way, not just for paper but anything.
Even food, the massive change that pesticides, fertilizer, and crop rotation(huge!), safe canning, refrigeration, all these things mean that food costs have plummeted.
Even different strains of crops, storage methods, the last century has seen yields increase immensely from the same land.
> To put this in perspective, the average laborer making 6-12 pence a day could purchase up to 75 sheets of paper with a day’s wages.