Stephen Colbert announced on Thursday night that next May would mark not just the end of his run as host, but the death of The Late Show itself, a CBS institution that has existed since 1993. “I found out just last night,” Colbert told his audience. “Yeah, I share your feelings,” he continued as they booed. “It’s not just the end of our show, but it’s the end of The Late Show on CBS. I’m not being replaced. This is all just going away.” Let me explain how we got here. To understand why The Late