Like I said yesterday, there's, like, five players in Murray's salary range who are more productive than he is; Murphy happens to be one of the five. Saying that he's not doing as well as a borderline All-Star is not a particularly compelling argument that Murray is underperforming... I'm not sure I'm prepared to buy your conclusion that Dyson Daniels is more productive on offense than Murray is, though?
But he hasn't regressed "overall," which is part of the point. Murray has regressed as a shooter, and no place else. He has either improved or, at worse, stagnated in every other aspect of his game.
No, he isn't, which is the other part of the point. Technically, he hasn't even started getting paid under his new contract yet. When he starts getting paid under his new contract, he'll be making $24M a year. This isn't the nineties: in 2026, 24M isn't MVP-caliber wing money. It isn't All-NBA-caliber wing money. It isn't perennial All-Star-caliber wing money. It isn't even "well above average" wing money. In the "modern" NBA, that's the going rate for a regular-degular starting-caliber multi-positional NBA wing, which Keegan Murray is.
I think that most reasonable people will agree that Murray has a lot of room to improve, particularly on the offensive end, and literally nobody on this message board has said that Kings Fans should be satisfied with where Murray is at right now. But, if he doesn't get any better, he's getting paid what the market says a player of his caliber should be getting paid, and the fact that he's not overperforming his contract, like Murphy is, doesn't make that untrue.