Let's play this out. You create a city of say, 100K, composed of employees from Google, FB, Salesforce, etc. Where do they eat? How much will housing cost given your average income will be several times that of a "normal" city? Do you spread them all out in single family homes (and have massive traffic) or do you force them to live in high-rises?

Where do the restaurants, and arts, and culture they need come from? Who works at those institutions, and how do they afford to live in that city? (Or do they commute from somewhere else?) How do you fund the international airport that's going to be a must-have?

I think it's possible, but I'm unclear how it would actually lead to a low cost of living. It sounds like most company towns - sprawling, lacking the kind of culture that people want from a city... reminds me of Plano, TX, where JC Penny moved in the 80s, or Bentonville, AR, or Sidney, NE (where Cabela's is HQed).

Companies would have a really hard time hiring highly-educated, high demand workers to move there vs being able to live in say, NYC, London or SF. It's not enough to just offer cheap housing - you have to offer a high quality of life, plus jobs for spouses, and good schools for their kids.