Tennessee Athletic Director Phil Fulmer suggested, Clemson HC Dabo Swinney supports:

https://www.postandcourier.com/columnists/sapakoff-a-spring-football-plan-clemson-vs-georgia-south-carolina/article_7ddc9e80-515a-11e8-b97a-5fd8f082f646.html

"I'd be the first to vote for that. We're the only level of football that doesn't have anything like that. You want to have a chance to gauge where your team is where you're not as familiar."

Swinney is right: NFL and high school teams get a lot out of exhibition games or scrimmages against other teams.