Karpov was a good little communist. He was just perfect for those in power as he pronounced their values and didn't rock the boat even slightly, and he looked to be strong enough to defeat all rivals.
"We have a world champion. We don't need another" was the sentiment when they regarded the up and coming Kasparov.
I read somewhere that Karpov was the intended successor of Spassky, and that the Soviets favored Karpov more than Kasparov, despite boths apparent skill, and that for some reason they pushed Karpov into the spotlight and tried purposefully hindering Kasparov for a while. And that it wasn't until Kasparov really started picking things up that they could no longer ignore him. Is this accurate? If so could others give more insight.
I wish I could elaborate more, or atleast give my source but I don't remember it.