You'd be amazed at what the VGA chipset can actually do - it's not called the Versatile Graphics Array for nothing.
Erm - VGA stands for
Video Graphics Array. And there have never been
18 bit deep modes...
Plus: 15 or 16 bit HiColor modes are not palettized, of course - imagine a 48 KByte RAMDAC (single chip!) running at ~100 MHz in 1990... HiColor and TrueColor modes work by bypassing the RAM part and feeding directly into the DAC part.
Imho VGA was the first usable video standard on the PC platform - MDA, CGA, Hercules and EGA were total crap when it came to graphics. When it came to 'magic' like changing display properties on the fly (like Copper does), VGA was inferior to Amiga graphics by far. However, later VGA chips added so much performance that it became unnecessary to play with the modes...
