Late night talk shows are extremely cheap, compared to regular scripted television. It's one of the reasons why NBC was so excited about moving Jay Leno to 10pm when Conan took over The Tonight Show:

The Jay Leno Show WILL be significantly cheaper than any primetime scripted show NBC could program. Primetime scripted programming usually costs about $3 million per hour; so the five hours NBC is revamping would total about $15 million per week. This new Leno show will cost NBC less than $2 million per week. ... So, not only does NBC get to KEEP its primetime hours, it gets to program them with a more cost-effective show.

https://www.writersdigest.com/industry-updates/jay-leno-nbc-...