Who ever said you would get a Balao ? Or even start in 41 ?
Though I can imagine it being a hard question to answer if you don`t know what you will get by going for 1 sub , but you do know (or think you know) what you will give up.
Maybe if it could be made more clear what is to gain by going for one ship people will be more inclined to go for that.
Though I can understand if that is still not 100% known at this point.