In the 1980s, many 8bit and 16 bit computer systems were available. The most successful one was the Commodore 64, and in addition there was the Amiga 500 and the Atari ST. These systems were sold for a moderate price and were equipped with mid range graphics and sound capabilities. The period of home computers ended at a specific year which was 1991. In this year, the VGA card for the IBM PC were introduced to a mass market.
On the first look the ISA VGA card doesn't look very impressive. But it was the major cause why the IBM PC has superseded the former home computers. The VGA mode 13h provides a resolution of 320x200 pixels with 256 colors. This spectrum makes games looking the same like on an arcade machine. In addition the VGA mode provides a better gaming experience than even on the Amiga 500.
Before the invention of the VGA mode, an IBM PC provided only a low amount o colors in the CGA resolution. CGA games are looking poor compared to the Commodore 64. In other words, the decision for or against a certain computer system is made in respect to the graphics card adapter. The VGA card was a revolutionary technology which allows to use an IBM PC as a gaming machine. It is possible to use the mode for creating well looking games. Here is a comparison table from the early 1990s:
Commodore 64 (1982), 160x200 with 16 colors
Atari ST (1985), 320x200 with 16 colors
Amiga 500 (1987), 320x200 with 32 colors
IBM PC, VGA resolution (1991), 320x200 with 256 colors