I have a feeling we are roughly in the same age group and have both experienced the birth of computer gaming 
Yes you are probably right about how the value of money itself has been decreased over that amount of years, but it isn’t really as simple as that 
No this I do not agree with, I have a feeling that you may have worked in some sort of development or have some know how about it, but your example is absolutely not correct, and here is why…
In early 80’s and 90’s pretty much all games were developed with little or no visual aid or assets, the programming tools were very simple compared to todays standard, engines like Unreal and assets of all sorts are widely available today, coding and tools to do it has definitely changed a lot over the years, also worth noting is that games after being developed had to go through a lot of testing because you simply couldn’t release a patch to fix bugs later on.
Games back then were sold as physically copies which meant an extra cost besides the actual development and testing phase.
These games were often produced in quite a higher amount than was ever sold to consumers, which meant that some in the chain ended up with copies they may never get sold, I bet there are still boxes filled with games from those somewhere in storages, so they just upscale it with lost value of money itself over the years is simply wrong, there are so many factors involved that makes it wrong to assume so.
For example I remember in the early 80’s where I bought my first videorecorder, I cannot remember what I paid for the first one, it wasn’t a vhs, betamax or video 2000, cannot remember the brand or format, but it was very expensive, in fact I think it cost several monthly pay checks to buy one 
Lots of tech cost an obscene amount of money at that time, color tv, stereo equipment(Hi-Fi), it mostly cost a lot of money, much more than anyone would be willing to pay for something like that today.
However I do remember at some point in the early eighties buying a video 2000 for roughly 3000 dollars(loosely converted from my local currency)
so with your example of 50$ being roughly the same as 120$ in todays money, a device like my Video 2000 should cost close to 10000 dollars today?
Things are not this black and white, lots of things have changed with just about everything we produce and sell, we have over the years gotten more efficient, production cost has been lowered by a lot for many things over the years, granted things has also gotten more advanced, but you simply cannot just put in a factor and say this is what it cost then and this what a similar thing should cost today, it simply doesn’t work like that, and it definitely don’t in development no matter if it is games or other software, so many things have changed in the process, back then you heavily relied on selling to the right price to as many customers as possible… Todays live service games are a whole different story, the focus is not so much on getting a lot of customers, but more importantly how high can we set the price without losing money compared to amount of potential customers, the drive is not so much about the quality or amount of units sold.
I wouldn’t be surprised if the whole live service concept with fomo, whaling and other techniques to keep players in the loop while trying to sell them ingame items for as high a price with as little effort as possible, at some point just blew up and people generally started to say no in a way so they can feel it, dunno if or when that day comes, but no matter how much I love conan Exiles, I wouldn’t shed a tear for the company and their practices 
I wouldn’t be surprised if there were some who would, personally I wouldn’t do it even if it meant little to the amount of money I had, I simply just wouldn’t, I consider value higher than a want for nice things 