Ben Rich expanded on Johnson's advice regarding the Navy in his book, although I think he also conceded that the Navy has some pretty good engineers.

Imho, the service branches are defined by and structured around the type of equipment required to complete their missions.

The Navy builds years-long expensive ships, then sends them halfway around the world under command of someone. It has a structure to facilitate that.

The Army (at best) efficiency organizes a huge amount of people and material, and it deploys and sustains it wherever needed. It has a structure to facilitate that.

The Air Force procures, operates, and sustains the most technical platforms. So it's gotten halfway decent at doing that, or at least learned some lessons from repeated mistakes. It has a structure to facilitate that.

(And the Marines scrounge through everyone's trash bin, cobble something together, and come out armed to the teeth)

Point being, if you look at the people who have risen to the ranks of power, they've been moulded to fit their service culture. Which means some services might not be as good as procurement...

The new hotness is the Constellation-class frigate which chose a mature design to keep costs down. That was until feature creep completely consumed it in record time:

"At one point the Constellation design shared about 85 percent commonality with the original FREMM design, but the alterations have brought that commonality down to under 15 percent, a person familiar with the changes told USNI News."

https://news.usni.org/2024/04/02/constellation-frigate-deliv...

Depends on what you mean by “working.” DDG-1000 is still kicking around trying to figure out what to do with itself. DDG(X) is in a requirements development phase. FFG-62 is actually getting built. There are various autonomous surface and sub efforts that may turn into something.