Yes, games today are cheaper when adjusted for inflation, but there is a big difference between games today and back then. The games back then were completed.
Games today might be cheaper, but they are often riddled with bugs, and sometimes cannot be played without getting an update. Not saying older games were bug free, but games today are released with bugs that are intended to be corrected later on.
Another issue with games today is DLC, either free or paid for. Older games were completed when you bought them. If there was more content, it was released in a sequel. To compare what an old game would be like if released today, TLOZ A Link to the Past would have been released with the Dark World part of the game as a paid-for DLC.
DLC wouldn't even be that big of a deal, but the DLC could be pulled at any given moment, leaving a modern game not fully playable. Compare that to any of the old games, that could be played at any time (as long as they still work, obviously).