They have a good enough 1 and 2 to be a contender but the 3-10th men aren't championship level guys. Look at title teams throughout history and there's always a clutch shooter off the bench, for example, we don't have that. We don't have a consistent 3rd option either. We don't have a lot of things that make this a championship level roster.
After KD and Book, Ayton is the only other player that would be a starter on probably half the teams in the league. CP3 wouldn't be in the rotation as more than a backup in Boston or Denver, who are legit contenders. Craig and Okogie would be situational role players while they're are 5th and 6th best players. That doesn't make a championship level roster. Monty isn't the issue, depth is.