Definitely amplify's risk for sure. If the company went under, your whole county would go under and the government is not likely to bail them out like they would a city who had too much debt. Since you may even purchase your house on the company land, you could quite literally lose everything.

Again, if the population thrives the amount of space is hyper-limited. I don't know if there'd be gentrification per say, since it'd be gentrified from the start but the populace would grow fabulously rich off both stock in the company, increased land value and general prosperity for your entire community.

It also changes the incentive structure. You want you company to thrive, so your can community to thrive and vice versa.