We have better transport tech now. Also, a walked city these days, if it had access to good water, would be pretty easy to sustain itself.  

 That's true. We could just fly in supplies. 

 Or just grow its own food and generate its own power. Sure, trade is generally good, but not reliance on said trade.  

 Lol. I like these discussions. LOL! We can always count on Stella! 🤣