I was reading someone's review of an out-of-print RPG and ran smack into the phrase "the mechanics are probably a bit dated". It's certainly a meme that's been floating around for a while. You don't want to play *old* games, because their mechanics are out of date. They stopped working decades ago, and it's hard to find dice, pencils and paper that are compatible with those old mechanics. You will have more fun with modern games that use cutting-edge mechanics, designed for *modern* paper.
Not to pick on the author of that review (he's actually saying the out-of-print game was pretty fun.) But the idea that mechanics can get out of date is farcical. OK, maybe there's a really old mechanic based on something a 21st-century gamer would have trouble finding or using, like haruspicy. But dice don't suddenly roll a different way, and pencils still work the same way they worked back in the early days of role-playing games.
What's happening is that people are confusing added value with necessity. For example, a new kind of mechanic now called Fate points evolved out of the way some early RPGs handled wishes. This is an idea that some people enjoy (I actually don't.) Thing is, the fact that older RPGs lack Fate points doesn't mean that they are "out of date". You can play a game without Fate points and have fun; people do it all the time. Fate points are an *additional* mechanic, available for those who want them, not an update to old games that makes old mechanics obsolete. The same applies to any "director's stance" or collaborative creation rules; I have played and enjoyed games that use these, but I wouldn't want my main role-playing game to use them. They aren't a "better" mechanic that makes the old "GM control of setting" approach obsolete, and they are even counterproductive in terms of fun when used with the wrong group.
And that's not even touching the idea that a lot of so-called up-to-date mechanics are crap. At least, from my perspective.