got writers?

My question is do late night talk show hosts really need writers? I understand the writers create monologues and other stuff about the show, but shouldn't Jay, Dave and the rest have enough experience to do this on their own? possibly adlib something of a show? or are they just supporting the strike by shutting down? Either way It doesn't bother me, I'm just wondering. The writers likely have a legitimate point, though as a casual observer I can't say I'm taking a position. so that's it, ignorance, but inquisitive.