There's another reason, I think. Making a site look fashionable (and web design is really like the clothes industry in that sense) will require the authors to

There's another reason, I think. Making a site look fashionable (and web design is really like the clothes industry in that sense) will require the authors to revisit it avery year or so, whenever the design fad du jour changes. While black text on white background is like jeans and t-shirts - not too hip, but always acceptable.