Well, what you need is radar and missile coverage. How do you get enough radar there, and float enough missiles. A big ship is cheaper per missile than a small ship.
Then there is the issue of protecting the big ship. This is possible, but they need a paradigm shift for the lasers they have. They have 300kW lasers (going to 500kW). They need ~2MW. This is a physics problem. However, we can point 10x 300kW lasers on the same target without issue. This is not a problem, and with such a system, we can defeat hypersonics and drone swarms.

The last issue is cost vs size. If you look at shipbuilding costs, the cost of a surface ship is proportional to the tonnage, with high-correlation. That is why old-timers in government don't believe anything about lower cost shipbuilding. However, the cost of a cruise ship or other navy's ships do NOT follow this same trend. We need to get the RIDICULOUS NAVSEA organization and SUPSHIPS organizations the phuck out of the way. They are worse than dinosaurs.

For example, the Navy has it's own welding requirements and certification. If you want to make equipment for the Navy you MUST weld and braze to these requirements. Every welder and weld type has a separate certification. This means that the 1,000's of American Welding Society (AWS) fully-certified companies can NOT supply for any equipment going to the Navy. Who do you think knows more about welding, the thousands of people in AWS, who like IEEE or ASME study and improve welding year over year OR the 40 people in the NAVSEA welding code in 05? My brother eliminated NASA welding requirements and switched to AWS 14000 (flight safety) requirements. You can add an inspection on the weld, but not a unique weld requirement. This increased NASA's supply base over 10x! Just one stupid thing, but a perfect example of why we can lower the cost of our ships. It is NOT greedy shipbuilders, it is incompetent Navy specifiers and requirements.

If the prior Philly Shipyard, now acquired by Hanwah (Korean conglomerate and shipbuilder), gets engaged and we get NAVSEA out of the way, you will see some real affordability transitioning.

Certainly you could have superior knowledge. ;^)
Is the 'protection' cost and the construction costs of such ships the most economic use of scarce resources? Can the so-called projection of power that those ships arguably provide be done using more economic advanced technology?

I would generally agree, but think now (perhaps I have superior knowledge) that protecting a big ship, like a CVN, is possible.

We already have this problem, regardless of building BBG-47

Note, I did limit my restriction to big ships.
They are sitting duck targets for modern technology.
I think Trump is under pressure (by the folks who killed JFK, shot Reagan,
and shot at Trump) to keep spending on military. Ship building is also
a way to give union members jobs, a political and personal survival choice.
Unfortunately, it's a case of fighting a war from the previous century,
ignoring the fact that they've been losing such since 1945 any time the
opposition has any capability to resist past a week.

Well you can certainly cancel the Army. It has no role in foreseeable warfare.

We disagree about Navy ships. Although you can clearly make them cheaper... a LOT cheaper. The path to that is to get NAVSEA OUT of ship design and specification. They are incompetent. Just the welding requirements are ridiculous. They require RT films for certification. Digital (you know, like at your dentist) is not allowed. Tell private industry what you want it to do, and let them design and build ships.

About 50 years after the treasonous structure should have been ended.
It has been obvious (to anyone with at least half a brain) since the 1970's
that the CPB was a front for communist propaganda.
Funding it was effectively suicide for individual liberty.
Thank you to the current administration.
Now how about cutting the military budget by $500 billion a year?
Building big naval ships is a YUGE waste of money by the current
administration.

Indeed. I actually thought this would never happen, but here it is. If the Dems win the midterms or the next presidency, they may try to revive it.

Promises made, promises kept

It was a left wing indoctrination scam right from the beginning. Oh my! No cafeteria in DC with the sushi chef! Big bird may have to get off the dole and get a real job! Boo-hoo-hoo! Now the local propaganda outlets are going to have to survive on their own. They will be competing with the Main Stream Marxist Media for survival.