The point is that AH graphics engine is very scaleless. It generates very nice graphics on good cards and allows to play on weaker PCs.
Very nice graphics? That's quite an exaggeration. Calling them "mediocre" is being generous.
This is a screenshot from Fighter Ace, which was last updated nearly 10 years ago.
Notice the much higher polygon count in the game engine, higher-res graphics overall, more efficient use of standalone graphics card, I could go on and on. And this is from a now-dead game that was last updated 10 years ago.
In 2002, I was playing that game, FA3, on a laptop with an 8MB (yes, 8MB) video card and an 800Mhz processor. These are screenshots taken while playing on that very system. Note: this is what the game looked like on BARE MINIMUM settings.
More to the point, I can run Battlefield 3 (the last graphics-intensive PC game I purchased) at all High, some Ultra settings with my current video card (AMD 6970 2GB, which was a $500 video card two years ago) at 60FPS. This game, which hasn't been updated for longer than that, maxes out the card at 40-45FPS with all settings on max. There is a severe lack of optimization going on.
I'm not trying to diss this game or its graphics, but the "it would be unplayable for the majority of players" argument can only be used for so long. This game's graphics are absolutely archaic, and the idea of keeping them that way to maintain the playerbase is preposterous. Firstly, there are many games (such as Fighter Ace) that had much better graphics and are more than a decade old, so we know for a fact that it's not a limitation of computing power, even on older systems. Secondly, if so many players here are running machines that are so significantly underpowered that they can't handle something (such as adding clouds to a game, which was tried then removed from the MA due to performance complaints), then the playerbase is virtually irrelevant because the second they're gone (which
will happen with eventual required OS and ISP updates), the game is dead.