This stems from the many reports I read about underwater missiles being tested by underwater pontoons. How come nobody is thinking about making single missile silos that can be in un-manned ' smaller' submarines and avoid the need for humans to man them?
With no need for Oxygen generation one can have deep submerged submarines just moving around with almost no detection. even if detected - no loss to life.
You would have a mini unmanned sub capable enough to remain underwater for months, at locations far away from base. It would need to send/receive massages secretly while remaining 100s of meters underwater. Both of this are pretty difficult.
The frequency for radio communication used for long distances 100s of meters underwater is below 100 Hz, not good for large data communication needed to direct the sub. Only US and Russia as yet posses the tech for such frequencies. Also, due to frequent needs to contact the base, the sub will be more vulnerable, reducing the stealth factor which is the speciality of subs.