I'll agree that a good game with good graphics can be more visually immersive than a good game with basic graphics, but a bad game is a bad game regardless. That's my point, graphics don't make the game, they merely improve it.
Also, hi-level graphics leave less time for the processor to deal with other stuff, so focussing too heavily on graphical impact can often lead to stuff being removed in order to support those graphics. I'll admit that is down to hardware, rather than software issues, but it's still a factor that can, and does, have impact in some games.