YOu can see the tower and it's protusions from as far away from the strip as Goodsprings. There is no real reason to go to the roof and there are no rocket ships to go into space and see the satelites. On the other example they are trying to sell the idea of a Vault that never opens but somehow a group of teenagers managed to get Leather jackets just to sell a cliched greaser visual. So it basically breaks the intended narrative with stupid aesthetics. Which is a pretty stupid move. It's as if I was trying to sell the idea of a character who has ben sheltered since childhood in a room and never was even allowed to read or see the sunlight but the first thing they do it to out of nowhere start quoting The Fonze and make internet jokes.
We know Vault 101 was opened at least once when they allowed James and his son into the vault. If you logged into the computer in the overseers office before leaving you found several files on the surrounding area as they had sent scouts out. The files mention the ants and the existence of Megaton. Then when we get to Megaton Moira has vault 101 jumpsuits in her inventory and I think she gives us an armored 101 suit as a reward at some point. This would tell us the vault has been opened more than just the one time.
Yes the leather jackets were a little silly, but given that we can find leather armor in the wastes, and the scouting runs, it is at least a tiny bit possible that they either found leather jackets in the wasteland, or tanned some brahmin hides into leather. Even if we don't see a library, I don't think it unreasonable to think they might have some sort of file system on the computers that would have historical information on it, and some of that info possibly being popular culture references.
And another idea that just popped in my head may be that they used leather holsters to create their jackets. The leather is stiffer, but could be made compliant over time.
As to why we don't see canons on a building in New Vegas, it never occurred to me to look for them, but a sophisticated laser canon system would likely be retractable so as not to draw undue attention.