Theoretically, buuuut...
Well, not to quibble, but you can just pick up a suit of power armor, several of them, right at the general store. And they restock regularly. It's part of what made the entire concept and execution of San Francisco so problematic. The notion that a bunch of seamen managed to construct a scientific miracle palace from a wrecked submarine is a little preposterous. The fact that they regularly crank out some of the most advanced tech in the world (for their tourist trade, apparently!) with access to little more than sand, fish, and scrap (and yet remain a community of impoverished fishermen whose most seasoned guards boast nothing more than silk shirts and small arms), let alone the idea of anyone in the wastes being able to "perfect the Vertibird within a year," is out-and-out mindbending. Even if we were to accept without batting an eyelash that the Shi were the most scientifically advanced faction in the post-nuke world (which in itself is dubious, supercomputer or no), they're one city isolated on a peninsula in a world that was running out of the relevant resources before they even got started. Even the sprawling, mighty NCR doesn't have the kind of manufacturing capacity and supply chains necessary for those kinds of expenditures.
Chinatown was intended to be a power cache for the player character. "You've reached the end of the game, here are all the badass-making goodies you've been hoping for." There's no real logic to back that up, and the devs must have been on a solid Kung Fu cinema kick when they did the quest writing, to boot. If San Francisco were to re-appear in any future game installment and be taken at all seriously, the whole affair would have to be taken with several dozen grains of salt. To my mind, that means their top tech level should probably only just barely manage to make them the envy of the other high-level post-nuke governments, and even there only in a few areas of specialization.
It might help to underscore the hierarchical chasm between the citizens and the ruling body, too-- the higher-ups spend all their time in the palace developing these old-world legacy goodies, but the peasants sure aren't seeing any of it. No one ever came out and said it in F2, but the Shi were practically a feudal society. Despite the generally innocuous way they were sold and the warm and fuzzy "Shi Empire" ending slide, I actually find the whole thing to be kind of dark.