According to your link, DDR5 today has the same price in real US $ as DDR3 was in 2014, during a brief spike towards high prices.

Since that peak in 2014 until today, the prices were lower than now. The peak in 2017 was more than 10% lower than today.

To reach permanently higher prices than today, we must go backwards until 2011.

So we have already regressed at least 12 years into the past, but more likely 15 years, and it is unknown how much more we will regress.