Building a new town is ridiculously simple. You can buy vast tracts land for pennies and do it today if you want – most of North America is open and available. Canada in fact is one of the most sparsely populated countries in the world. You don't need permits, heck you don't need any permission at all. In fact there are entire such towns available for purchase.
But that's not what you really want, is it? You want a house in a fancy urban or suburban zip code with good services, schools, weather, parks, restaurants, social life, industry, commerce, transportation... That is going to cost you, because everyone else wants the same.
And still, even with ~50,000 acres and a bunch of billionaires behind them, the media coverage seems to agree that they'll be fighting against regulations and red tape and NIMBYs for years, to actually build anything useful. With success far from assured.
But that's not what you really want, is it? You want a house in a fancy urban or suburban zip code with good services, schools, weather, parks, restaurants, social life, industry, commerce, transportation... That is going to cost you, because everyone else wants the same.