There's a scenario that plays out where Giannis gets unhappy. If everything went perfect, they would be contenders.
However...
Parker has serious injury concerns.
Middleton is good not great (more like the 4-5 best player on a great team, not the 2-3).
Maker is a decent role player, but only good not great.
Brogdon is good not great.
Henson, Monroe, and Teletovic are decent but all have drawbacks.
Snell is basically Iman Shumpert.
How high is Wilson's upside?
This is a team that is capped out, and they will likely reach their ceiling this year. They have serious shooting limitations and a stagnant offense.
Their defensive potential is elite, but I'm not sure they can consistently rely on Giannis to be elite offensively and the anchor the defensive without help.