More recently, in the north we tried placing new cities, turns out that people don't go and live somewhere if there isn't work, and there isn't much work in the north. Those cities are now failures. Heck, the big established cities in the north are being drained by people moving towards the cities in the middle.

Cities grow organically because people want to live in that city.

That doesn't mean you can't stimulate that growth. You can take the initial steps to make an area a little more desirable and then let the rest happen organically. Nobody will randomly desire to live in an empty rural area.

It's a bootstrapping problem. Sometimes a single employer can make an area desirable, but that single employer may never move there because it's not a desirable area.