This may seem a little bit arbitrary, but this is not uncommon throughout history. For example, in a normal English literature class, you’re going to be assigned Shakespeare. You will be assigned a bunch of novels from the 19th century, but not very much in between. Yeah, sure, there are a few works, probably, from the 1600s and 1700s, but not many compared to those other ones that I mentioned.
Video games might be the same way, where the games that were made from the NES to around 2010 are the ones that people care about far into the future.