I guess my point was, that even though Collins is a massive improvement and much more modern than the o-boats and physically larger, it is hardly luxurious and is not wasteful in its space. They are different. Sure there are less bulk head doors, but the doors on collins seemed more awkward to get through. It ain't no surface ship. But it feels like a different century to the o-boats.
Certainly in comparison to large nuclear boats. People were still sleeping on top of or underneath torpedoes, you are still in close quarters with people. Many spaces are still tight and you other complexities like more computers and systems, mixed gender crew. Sure collins even has a gym, they proudly showed me the rowing machine they had tucked away under the torpedos, which they can pull out and use in corridor. They also had a nifty toilet/sink combo in the engine room.
But it isn't like you see on say the US submarine.
Just chillin practicing yoga and telling yarns in the gym in the sub on a Virginia class.
I am sure a near 9000t surface ship sounds like a cruise ship for those that served on ships built immediately post WW2. But I am sure in the end it will be fitted with more stuff and crew luxuries will be an improvement but fairly minimal.
I hope the new subs are a bit roomier.