Yeah but if Exum takes a step forward (which tbh seems like a stretch at this point) you have to pay him and you are going to have to pay Paul George that same year. You probably can't afford an improved Exum and a maxed Paul George all while paying BK his final 2 years.
Which kind of brings up the point of if Utah is willing to have 3 max contract players at once (PG, Hayward ,and Gobert). I'd assume if they trade for George that would be an indicator of "yes" in this scenario, but that would kind of make keeping an improved Exum impossible.
Or you can trade Exum for something of value. We'll cross that bridge if we get to it.