Remind me again what their salaries are? There's a difference in expectations when you're being paid max money which equates to being THE GUY. If we paid Fox $16mil/yr you wouldn't hear me wanting to trade him at all.
To be fair, when Murray signed his deal he was (a) only one year removed from missing an entire season with a torn ACL, and (b) averaging 10.9 ppg, 4.1 apg and 5.8 rpg while playing 25.6 minutes a night.
He was a solid piece at the time, but he's been a definite outlier in terms of how much development he's made this far into his NBA career.
Even pre-injury it didn't look like he was going to be more than a rotational piece as a good defensive guard. To seem him make a leap in his fifth season (sixth in the league total, but as mentioned he missed all of the 2018-2019 season) at age 25 is pretty unexpected. For comparison, we think of Giannis as a guy that entered the league as a long term project and he was an all-star in his fourth season when he was 22.
IMO, Murray signed a very reasonable deal that could have even been considered a slight overpay by the Spurs at the time and based on his production up until then.
Is Fox overpaid? Up until this year I would have said no. He was making the kind of leaps you want to see and had he come into this season and put up even better numbers we wouldn't be having this conversation. It's only because he regressed this season (or at least so far this season) that the max deal seems like it might be a mistake. At this point I'm not sure what concerns me the most - the decline in his game, the change in his attitude, or that he's continues to miss games and no one is sure why.
But the other problem with Fox's contract is based on the failure of the Kings to build a winning roster. I think most of us agree that on a contending team, heck just on a team that consistently makes the playoffs, you'd want Fox to likely be your second best player. But in failing to draft someone that would make Fox the #2 guy (or even 1B) he was forced into being the best player. With that being the case the Kings were going to need to max him out or trade him. They really didn't have any other options.