I'm still figuring that one out, hah. I think if the culture was strong enough and public transportation was "perfected" within the cofines of the 100acres people might gravitate their under normal market pressure.
Otherwise I guess you could just make it cheap. For those reading -- what would incentivize you?
Well, what incentivizes people to live anywhere? Wanting to live near people like themselves, and wanting to not live near people unlike themselves. Living where they can afford to live - most people would like to live somewhere like where they currently live, but nicer (which they can't afford). Tradition... live where you grew up, where your family has "always" lived. Etc.
Something to think about here... Noodles and Company. You know what their ad budget is? Zero. They're entirely location-driven. They build only in areas that satisfy certain economic criteria. People who frequent those kinds of areas recognize them from style and previous experience. They know who they want their customers to be.
So you don't start with "I want to build a certain way". Start with "I want to build a community of a certain type of people, with particular incomes and social values".
For example, my spouse and I live in a hundred year old house in a quiet Minneapolis neighborhood. We could have two or three times the space (inside and out) if we were willing to live in the burbs. But we live in the city proper for shared values... access to the artistic communities we love. We live where we can count on most of our neighbors to share our political values. Where we can get the diverse food we like. Etc. And if we had more money, we'd just live in a more expensive version of the same area (heck, my wife's dream house is about four blocks from ours, an old mansion on the Mississippi).
As a millennial, incentives for me would be a well paying job market for my career, diversity of food options, accessible outdoor activities, and an efficient metro system. Though one could get all that by living somewhere cheaper in the suburbs but sacrificing time to commute to work in this dense metropolis. Also, I do appreciate having a reasonable front/back yard. Maybe its an outdated feeling, but owning land that you can do almost anything with is empowering.
I personally would not mind living in this hypothetical place while I am young, but I would definitely not want to stay there in the mid-long term.
In a lot of Americans cities jobs are spread out in the suburbs. In my southeastern US, a bank recently located a large office presence from downtown to a suburban area right off the interstate. I understand a lot of it was to do with a lack of space. However, in the past an employee had the option of living and working downtown at this bank. With the new office location, that option is non-existent.
Otherwise I guess you could just make it cheap. For those reading -- what would incentivize you?