Y'all aren't being fair to new games. It's like people who contend that no new music can compare to the days of classic rock. But the classic rock station is just like a top 40's station. It plays the same breakout songs all the time and, in spite of a classic rock station encompassing about 20 years-worth of rock and roll, you often will here the same song on the radio two or three times in the same day. Whereas a top 40's station playing modern music plays the top 40 songs of the year so they have a much smaller pool of music to draw from. It's the same with videogames. You've got a couple thousand ROMS on your cabinet, but you only play a tiny, itsy bitsy fraction of those and then judge the first twenty years of videogames based only on that tiny sample of the cream of the crop. The rest, which you seem to ignore when talking about games from that time period, are.......you guessed it.......completely derivative drek.
Most games, even great games, are derivative. This is true today and in the past, but every now and then you do get something totally different. Even Galaga is a derivative of Space Invaders. It just vastly improved on the formula. It's the same today. Half-Life was a breakthrough game that changed the FPS forever, but it was a derivative of Doom and Wolfenstein 3D.
Now, just as in the past, we get totally new concepts like Parappa the Rapper or The Sims or Metal Gear Solid or Tetris or Super Mario 64 (this one was a revolution in game design) or Dance Dance Revolution. And, just as in the past, the market is filled mostly with derivatives -- some great, but mostly drivel. Seriously, look through your Mame ROMS and tell me that the design mantra was different then than it is today. 95% or more of the games in MAME are effectively unplayable they are so bad.
The Ms. Pac-Mans and Smash TVs and Donkey Kong Jr.s and 1943s were the exception to the rule, they are not representative of anything like the majority of games that were being produced at the time. Oh....whoops....those games are all derivatives.