Unless it's a game that I'm super hyped about i rarely buy new games when they first come out. I always make a judgement call with any game and ask myself how much is a specific game worth to me personally and how badly I want to play it. As a result I don't buy a ton of modern games since their value continues to slip more and more (typically) over time. There have been those rare occasions where I held off on getting a modern title only for it to skyrocket in value and me kick myself later on for not getting it, but this is the exception thank goodness.
As for retro games, they've been out for a long time and their prices are usually pretty stable. Occasionally a game will get the attention of some huge youtuber or something else will shine a light on it again, resulting in a value spike, but for the most part I feel like retro game prices have normalized over the past couple years. Holding off on maybe a potential price crash on games, I feel a lot more confident buying a retro game at full price than a new game since I can be more certain it's price isn't going to go down in the near future.
So in conclusion, I feel like $60 is better spent on retro games, at least if you are concerned with the value of the game maintaining close to what you paid. However, one thing aspect I didn't mention is value for your money, which I believe newer titles definitely have the edge on retro games, but that is sort of a subjective thing anyways.