Yeah, it might be that Intel is overcharging for theirs, but they already set the expected prices, and AMD needs the cash, so why not sell for slightly higher prices?
According to an inflation calculator, there has been roughly a 20% inflation since 2009, so that price adjusted for inflation would be $1,200 USD for the top of the line processor.
However, the i9 9980XE is priced at $1,800 USD, a 50% increase.
I believe that rather than AMD underpricing, Intel has been marking up their prices since they have had a bigger market share and that $750 USD is a fair price for a top of the line AMD processor.
The real question here (which we won't get an answer to) is who's margins are better... somebody else's 7nm + chiplet design certainly make it easier to manufacture.
But also, Intel’s costs are going to be far higher since they’re using larger dies and aggressively binning. In contrast, with AMD’s smaller “chiplets” even the lower quality silicon (which they’re probably using in all the non-Epyc chips) can be utilized.