You have to take this in the context and the time period when negotiations were done. Bitmain was very successful at the time and they also thrived with a high Bitcoin price. Since then, the Bitcoin price dropped with almost 90% and mining farms are hardly making a profit these days.

Bitmain most probably never thought that this might happen in the future, so they made a lot of empty promises and they were also looking for cheap electricity to make even more profits.