You're new so it's understandable.
His edge comes from the beginning of the season. The further into a season, any sports season, you get, the tighter the lines get, because there has been more time to analyze. Let's use the NFL for example. No one knows what to make of the Panthers in terms of handicapping. Is the offense that prolific, or is Arizona's defense that inept? In two months it will be painfully obvious how good or bad Carolina is, and whatever line comes out in their November games, it will be pretty sharp. And by then he'll have said to give up on the NFL. By then he'll be focusing on college basketball/NBA and CFB bowl games.