A high-end chip fabrication line is a very highly-tuned system. It's not a case of just buying the right machines and slapping them together, even doing a copy and paste does not guarantee the right results. You need to spend a lot of time adjusting the process variables and troubleshooting issues to bring things under control, and then keep monitoring them to maintain that control because things will drift over time or further issues will occur. You also need to bring a whole new set of people up to speed with how the fab works, and they also need to learn the quirks of that specific one as they go. These fabs are already optimized for near 100% utilization of the machinery in them, so more people doesn't mean more capacity.