Because pure functionality doesn't sell. People like to have options and in general people like to have all the bangs and whistles. If you doubt, you can go to the WotC company info and the Palladium company info to compare. In 3 months, WotC will typically sell 100,000 copies of a new RPG book belonging to a popular product line. In 3 months, Palladium will typically sell 10,000 copies of a new RPG book belonging to a popular product line.
Also, the new core books have been promised to retail at around $20 they are hard-bound, full color and 320 pages. The key is that if you produce a superior product you gain a larger support base and therefor can offer your product at a reduced price thus increasing your demand. If Palladium spent more time on producing a quality product visually, they would likely sell more and then more people would play Palladium games. Just having all the information there isn't good enough for most people.