thats just not true. the ratings were an excuse, nobody in their right mind gives a guy a contract 6 years in advance then only allows them 7 months to make things work.
Sports teams do it all the time. You don't produce, you get traded. Breaking a contract will often be cheaper than the opportunity cost of keeping bad talent in a valuable position/time slot.
You think the studios care about anything except the ratings? How do you think they make money? Considering 22 episodes of any other primetime show is a whole season, seven months of crappy talk show ratings is more than enough data to justify rejigging contracts.
Whatever, Ferguson for the win! (But I'll likely just stick with Stewart/Colbert.)