Leaving a subsidy on the table is not exactly like leaving money on the table for either party. They lower costs and lower the tax revenue from a business, but they don't represent a cost (outside of the cost to negotiate and write the deal). It seems like calling the people involved idiots (or suggesting the entire company is...setting itself up to fail to execute?) requires knowing internal details of Foxconn's financials.

A $1bn increase in revenue would be less than a 1% increase for Foxconn overall. That suggests they're probably willing to bear extremely high costs to establish new sites, as long as those sites will eventually yield significant revenue. Their negotiating tactics here seem short sighted from my point of view, but when you're as large as they are you create your own conditions.

Edit: Like...this deal seems to allow them to operate any of their businesses in Wisconsin. If they decide not to, they burn bridges in Wisconsin, but they wouldn't care about burning those bridges because burning them means they don't want to do business in the state. It seems like all they lose is their negotiators' salaries, small (for them) facilities costs, and whatever general goodwill they lose.