I agree with Gypsy on this one. I think a lot of what makes an older title great is nostalgia more than anything. Sure, there are a few out there that will forever stand the test of time, but a large portion of the reason the games were more difficult was usually because of some bullshit control scheme (only having two buttons greatly limits what you can actually do in a game), or the game requiring muscle memory in order to actually be able to beat it (I'm thinking of games like Battletoads, the first Mega Man title, Super Mario Bros., Metroid, etc). None of these games were meant to be beatable on your first playthrough -- you were
meant to play the games over and over again in order to learn almost every aspect of the game before you were ever going to beat it. (Battletoads is an extreme example of this)
I realize these aren't the arcade style games that you are referring to, but arcade titles follow a similar rule. Those games aren't meant to be beaten -- they are meant to be enjoyed until you die. No one was supposed to be able to get to the kill screen in Donkey Kong or Pac-Man -- I don't even think the developers know that they existed. The enjoyment from playing most arcade style games was to beat your friends or to beat yourself -- the game was just the competition method used. Besting your own high score is a fantastic feeling, but beating your best friend's score is even better. That is what made those games thrive, in my opinion, and facets of those original arcade titles still exist in games today, just in different forms. Online leaderboards, time trial comparisons in racings games with people on your friends list, etc... they are all different forms of the same thing.
If the "games of old" followed the same rules as today's games, most of those games could be completed within an hour, simply due to memory storage on those small cartridges. That would not keep anyone entertained. Similarily, if games today followed the same rules as games of old, we would have games that take 100+ hours to complete being the standard instead of the exception (with pretty much the entire JRPG genre being excluded from that statement).
As games became more popular and more people started playing them, the "die-hards" (people who have been actively playing games for the majority of their lives) all seemed to start complaining about how most games of the modern era have moved so far away from their roots. Part of that is because games aren't really being created with them in mind anymore -- games are being created for the status quo, and the status quo does not want to pour 100+ hours into a game when they have so many other aspects of their lives going on.
The most interesting statement I've ever heard about video games as a media was actually in a comedy clip that I watched:
For people who don't feel like watching (although I highly recommend you do, it's hilarious), the basic summary: video games are the only form of media that will actually lock you out of content because you don't have the time to dedicate to mastering each game (and each game is just a little bit different) in order to finish them. This wasn't a huge problem in "the old days," when the content of a video game
was the gameplay, but now that people are demanding actual stories and whatnot with their games, it's become a bit of a problem. Do you punish people who cannot finish a game because they don't have in their daily lives to dedicate to playing it every day for at least an hour until they beat it, or do you make the games a little bit easier to complete so that people can actually enjoy the content that they bought without having to dedicate all of their free time towards it?
This is pretty much the argument that started the entire debacle with Jennifer Hale earlier this year, and it's one that will never be resolved, because every single person plays games for slightly different reasons, and finds enjoyment out of them in different ways. All I know is that the market trend for console/PC gaming has moved towards the second game, and I highly doubt that the first will ever be the standard ever again. Then again, the "arcade style" gameplay has resurfaced lately with social and mobile gaming, so maybe it will make a bit of a resurgence.
As for the argument of "old vs. new," I think a lot of that comes from when you started playing games. I personally started playing on the NES, and I still consider the games I played when I was younger some of the best games ever, because they defined what I enjoyed as a gamer. When I see most people's "Best of the Best" games lists, a lot of the titles on those lists are either games that they played growing up, or games that hold similar features to the games they played growing up. When I look at the games that I really enjoy now, they are all very similar to games that I grew up playing: Dragon's Dogma/Kingdoms of Amalur are similar to Ocarina of time; Alice: Madness Returns/Rayman: Origins are similar to Super Mario Bros. & Mega Man; Ratchet & Clank/Uncharted are similar to Jet Force Gemini; Demon's Souls is similar to Castlevania. These are some of my favourite games that I have played in the last year, and I can easily see their roots in several games I still play and love on my NES, that I grew up playing.