Fact is, the NEST is built like a bloody fortress. They try to hide the prison like structure, and only mention the capacity for lock-down in fine print of the EULA renting policy. But just think about it for a moment. Just the need to support a hundred story tall structure, much less resit the wind-shear they experience requires a sturdy build. Then of course, you need a way of containing disaster. There aren't enough helicopters in the world to get everyone out of the top fifty stories in a timely fashion should a fire start on floor forty-nine. Metal doors and fireproof blocks can spring into action at any time. Halon suppression systems are behind every wall - not so good for people - but imagine trying to pump water up that high at a rate equal to a hydrant - just the normal everyday use requires a system of intermediate reiviours and turbine impellers just short of jet engines.
And then there are the anti-terrorism and riot measures... I'll just give you this one example - look for little orange sort of half-moon designs covering Cog shaped holes. Those are quick connects to pump CS tear gas through the vent system.
Silly as it sounds, there really did run a few simulated zombie outbreaks in a few of the megastructures. Partly as an all up test, partly as a way to make humorous public safety instructions, and in at least one case they edited it all together into a full length movie to try to a few bucks out of it. Its doubtful that particular preparation actually helped, but all the other features certainly did.
Any NEST that didn't get completely overrun can still have between five and twenty thousand people inside of it. Five thousand is probably the upper size for most of the other city states. Or so I would guess. That Tesla place is an arcology itself, and the Government has a lot of stuff in Vegas, but the NESTS are still hands down the biggest.
That size is the great strength of the remaining arcos, though a weakness as well. On one hand, the megastructures never lack for labor, expertise, or services. On the other - keeping that many people fed and happy is a daunting task.
"Now see here, this is the problem - you keep going between personal observation and academic disorientation. Pick a voice and keep with it. Furthermore, doesn't everyone know this stuff already?"
"Stuff like the gas hook-ups - nah. You had to really work in one to know that. Not live, work. Which I did. And in turn I ended up as a Rapid Access Technician pulling old tech and clearing abandoned areas to help expand. If I'm going to tell my story, they need to know these things - right? Its not like everyone is going to search the entire Zone archive every time a new character graces the scene - yes?"
"Maybe - but if we're going to run the story its got to be new. Nothing is going to compare to when everyone learned what KC actually stood for, but come on - there has to be something new."
"I can take my story elsewhere."
"And the government can give it out for free as educational materials, or it can be released on the new sphere. Don't get so snippy, we'll work something out. So - to the beginning..."