Even if older games have an overall better ratio of good games to bad ones, I do think people need to give new games some credit. A lot of people seem to refuse to believe anything will ever best any game from the 16-bit era (which also goes hand-in-hand with the fact I think some people need to stop with the "it's better because it's old" mentality that is becoming all to common these days... Sorry, but some new games are indeed better than older ones).
The reason the 16-bit era was so great was that it had a lot of trailblazers and first-times (or simply better variations) for a lot of what we have today. Of course, platformers were the first person shooters of the day, but at the same time, a lot of it was fresh, and new. In order to succeed, you needed to build a solid game - The market wasn't as big as it is today, and there weren't as many "casual" gamers then, either. Games like Star Fox, Mario Kart, Super Mario World, Sonic the Hedgehog, and Gunstar Heroes are all extremely good examples of genres whose primary points were more or less perfected during this era or which were never fleshed out to begin with. Mario Kart was huge in the day for its pseudo-3D (well, kinda) tracks/arenas and competitive gameplay, Sonic the Hedgehog gave us a taste of speed which was before unprecedented, and Gunstar Heroes gave us silky smooth controls on a 3-button gamepad.
A lot of us grew up with that, and really, even if there are some good titles coming out nowadays, there aren't nearly as many good titles - much less great titles - as it seems there were in the 16-bit era. Even looking back at games I've never played before, like Clock Tower, Shin Megami Tensei, Seiken Densetsu 3, Tales of Phantasia, Chrono Trigger (yeah, never played it during its release), Final Fantasy VI (same), F-15 Strike Eagle II (yeah, it appeals to me), Vectorman, and Phantasy Star IV, it seems as though the lasting appeal is much higher, and the creativity and relative technology factor (not to mention relative polish) was through the roof.
Again, it's not that games nowadays aren't good. I mean, there are a few really good ones out right now that I can think of. It's just that they all seem to look
the same, play
the same, and tend to have poor production quality, especially if you look at games within the same genre. Not much really sets one first person shooter apart from another, and while that's fine, that's not an incentive for me to pick up the latest Unreal Tournament, for example.
On the other hand, Command & Conquer, for example, is one series that seems to have aged quite well, and I never get tired of Ace Combat. The gameplay doesn't really change very much between editions of these two series, but it doesn't need to - It's been tweaked and polished to the point where it's more or less great the way it is. New features are welcome, and new units/vehicles, new missions, and new stories are the major selling points, even though the major gameplay remains the same.
But it wouldn't be enough for another franchise to pick up on that momentum and do the same thing. It creates a mess, and the original games suffer for it. Halo is a great example of a good game that everyone feels is imitated too much, and really, it is. The basic gameplay concepts are used in many, MANY FPS games since, and really, it's to the point where the original game is called mediocre for it.
That's the problem. There are so many "Grand Theft Auto clones" and "Halo clones", and not enough fresh games being released. Mind you, Far Cry 2 and Fallout 3 are indeed awesome, as is Left 4 Dead, but these games are unique. Fallout 3 has only one analogue - Oblivion - which uses the same engine, and Far Cry's only real analogue is Crysis, which is really only analogous because they're both so pretty. Left 4 Dead is truly something new, but really, you could argue that things like Zombie Panic! did it first, and you'd be right.
I guess the whole point is, there's not enough examples of originality to write home about with gaming today, where in the 16-bit era, most of the games you're playing haven't really been done before, or major new features were making their first debuts. There was a huge density of great games during the period (as well as terrible games, but that spawned such awesome things as the AVGN), and really, a lot of it was verifiably great.