I am inclined to believe that the prices go down if the ability to get something for free exists.
I hate to use this as an example but they did a study on the price of various sex acts performed during the 1800s compared to today and they found that because of societal changes regarding promiscuity, the price for acts once considered taboo has dropped dramatically.
A more family friendly example would be the impact thay Spotify and Pandora has had on CD prices. Itunes just closed down because obviously theres no need to buy digital music anymore but Im not sure if it did anything to sales of CDs. Vinyl of course is a collectors item and would be a good thing to compare considering they are the equivalent of old video game cartridges in my opinion.
In 2019, I dont know how many people are buying physical carts to play games when you have myriad options either on streaming, compilation discs, piracy, etc. I buy them because I am a luddite but I have to imagine im in the minority