While most people wouldn't hesitate to travel 30 minutes out of town, the generally don't ever think to see if jobs exist 30 minutes out of town, and thus won't find the work there. When looking for work they search within the city they live in, not the next town over with a name they might not even know. This is a real problem for a lot of businesses that exist 30 minutes out of town.

In fairness, the companies behind these data centres are well known and have endless marketing budgets, so they can likely find a way to close that gap where the typical rural-based business cannot, but at the same time why take the risk when you can just as easily build the datacenter right beside the person you want to hire?