I agree that UUVs could play a big part in underwater warfare/intelligence gathering 10-20 years from now.
If you posit that submarines are going to be highly detectable (which is reasonable, and has been a risk since the '80's, when thermal signature tracking looked like it might become viable) then there's no particularly compelling reason why you would deploy UUVs from subs rather than from planes or surface ships.
For long term UUV deployments however you would have to deal with the "fuel problem." They will be more efficient than a manned submarine, and can be quite streamlined, but regardless moving water is expensive.
So, for example, dropping them into the water at Hawaii and expecting them to make it to China and back seems "unlikely" because anything large enough to have enough fuel to do that would also likely be detectable (which is the reason you aren't using manned submarines to begin with).
So maybe that's why they're talking about manned submarines as UUV carriers. So that the UUV can have batteries in them and electric motors, maybe 24 hours max of power, and only need to make it 1/8th of the distance otherwise.
Options for interacting with a target land location (dates extremely rough, in rough historical order): - Subsonic aircraft: outpaced by projectile-based anti-aircraft since ~1935 - Supersonic aircraft: outpaced and obsoleted by missile and satellite technology since ~1970 - Satellite: excellent for reconnaissance and elint, limited interactive capabilities due to treaty obligations - Subsonic cruise missiles (aka light missiles): limited range (relative to coastal approach), limited survivability against active anti-aircraft defenses - ICBM (aka heavy missiles): expensive, high risk of escalation due to detection, risk of nuclear payload, and ability to apply last minute target corrections - Carrier launched aircraft: limited range, limited survivability against active anti-aircraft defenses - Supersonic cruise missiles: limited range, limited survivability against active anti-aircraft defenses - Drones: limited range, limited survivability against active anti-aircraft defenses
You ideally want an aerial platform (freedom of movement, ability to interact with land targets), survivable in a hostile environment, as cheaply as possible.
This was solved by a carrier air wing.
However, the idea of A2/AD is to push the survivability line out far enough that the carrier can no longer approach close enough to let its air wing operate efficiently.
The obvious go to is to take a platform that can penetrate that A2/AD coverage to a greater depth with acceptable survivability. (It's a lot easier to hide a submarine than an aircraft carrier / it's a lot more expensive to build a submarine detection net across large ocean regions)
Then have that platform launch the equivalent of an air wing.
E.g. stealth submarines serving as carriers for limited-range (because that buys you design to make them stealthier / more survivable / faster) aerial drones
The "risk of nuclear payload" is only a severe problem if overflight is necessary. The RF would be able to assess that a non-overflying SLBM was not targeting RF territory as soon as it traveled through the radar nets. Obviously this is still probably a stupid weapon to use in a conventional context.
It's a good dive :-)