I don't see it happening for this team. It's a niche way to score and you need to build your team specifically for it. The Spurs are built for it and the Warriors were built for it but not so much anymore since the best mid range shooter in the game in Durant is gone. Also I'm not sure what stat he's using that has the Spurs 3rd in offense but I've yet to find anything that has them better than 7th or so.
If you go to basketball reference and look at the team pages. There is a section for shooting where you can line up the players FG% from 3-10ft away from the basket and 10-16ft away. The Kings as a whole were atrocious in comparison at both of those distances. From 3-10ft away, Fox shoots 36% and Hield shoots 24%! The best regular rotation player on the team from 3-10ft was Beli at 44%.
For comparison, Gay, Derozan, Belinelli, Aldridge and Poetl all shot higher from there than our most efficient guy in Beli.
After looking at those stats for the first time, I'm noticing that Fox can really improve his game by either working on the 3-10ft shot or scrapping it all together (I'd prefer if he scrapped it for the most part). He actually takes the 2nd most shots from that area than anywhere else on the floor. In comparison, Hield takes the least shots from 3-10ft than anywhere else on the floor so even though he shoots horribly from there, it doesn't have nearly the impact on his efficiency than it does for Fox.
I don't think the classic mid-range is dead in any way other than how it relates to the fact that physical defense and alpha one on one play is. Offense is typically a reaction to how teams defend you and the NBA has created a game where there is basically only one way to play. The game is easier on the eyes on average but I do miss the days of being able to build a team whatever way you wanted to that left you still viable. You had super defensive teams, post up teams, fast break teams, shooting teams, passing teams. Now it's kind of all shades of the same color. The genius of creating a basketball team in the front office is dead. The game used to be like chess in the FO, now it's more like checkers. Also, the Spurs are his example but they have some of the best mid-range players on their team so that's their strength anyway. If anything it shows you playing to your strengths is always the way to go.
The only way it makes sense to use it is if someone is shooting at a high enough % to outweigh the expected points per attempt - which basically means 60%+ with so many teams shooting 3s in the high 30s and elite players shooting ~40% from 3.
mid-range shots still have a purpose in the sport. It's not as if it's becoming extinct. Not all players are willing to adapt and expand their range, they play the way that got them in the league in the first place. Just because the league is shooting an insane amount of three point field goals doesn't mean players should pass up wide open mid-range shots for a three, unless you are passing it to a high percentage three point shooter like a Buddy, Klay, Steph, Korver, etc.