Graphics and gameplay are linked as someone else mention that a lot of the old classics were graphic whores at the time. Wii was an exception because of motion controls and exercise wii board. Anything that suppose to help you lose weight sell big in Amercia even if it doesn't work.
The reason graphics and gameplay are linked is graphics help sells game so investors are interested in graphics. Before a developer can sell a game to gamers they must first sell it to investors/publisher.
Better graphics can mean sometimes more time to develop and add to a game.












