The argument for or against a CSG or even an ESG is really an argument for or against sortie generation and the cost of doing that business. Yes CVNs are the single biggest line item in the NDAA, that said and as has been said in every major conflict and some minor conflicts by national command authority "Where are the carriers?". I didnt make that up and yes it's cliche but when POTUS asks that question, they are relavent regardless of what they cost. Why? Because they can get the job done when USAF assets aren't in place or don't have overflight rights to get in place when they are needed.

Additionally there is a huge strategic detterence and communication piece to the CSG and it's mobility and lethality. Is it vulnerable...sure, is it survivable in some conflicts...to be determined and debated.

There is a concept out there called the single Naval(to include the Marines) battle and in some cases it is a self licking ice cream cone, but at the end of the day when executed correctly the Navy/Marine Corps can function as the air, sea and land components simultaneously. Is it the best way to do businesss? Arguably no, but the capability is there and it is trained to.

At the end of the day each of the services rely on the other and their inherent capabilities whether its the targeting/Fires cell in the AOC relying on TLAM support or CSG sorties, or CFMCC leadership relying on PR assets from USA/USAF in theater. Its a team effort, sometimes we're just not very good at working as a team especially in fiscally constrained times when the services are vying individually for every dollar they can get.