When did college teams start adding the role of GM? I read the article and I'm wondering what would the AD do (other than hire staff) that the GM doesn't?

Handle the NILs. New job nowadays.

For high revenue teams Luck's GM position makes a lot of sense. Reaching down into the coaching staff with recruiting and up into the AD's position for fund raising and staffing, he'll have a lot of say into how the program evolves both during the season and in the long term. I can see other sports following this model.

I don't think it makes sense for UCD unless drooling idiocy has us setting our sights on BCS status.