I know that what matters in the end is the shipped game, so stating that these kind of landmarks were in the original plan doesn't really matter right now
This is a submarine sim after all and land plays a very small part in the gameplay. Given a smallish team, imagine the amount of developer resources put on this task.
The terrain/harbor technology changed from SH4 to make it look better, but that meant that all harbors had to be recreated. Even so, some new landmarks still managed to get in over previous versions.
BTW, did anyone get to see Christ the Redeemer yet ?