A calculator seems a bit simplistic but I would generally agree that if there isn't something outright drawing you to that area, you don't have to be there and there are costs.
I worked for a really large company a while back. They bought some smaller company and discovered a support center ... that I worked at. They thought they'd try doing support at that site as they suddenly had support there.
For less than half the cost per employee we managed to do twice the workload, higher customer satisfaction, and we often were requested by customers who quickly realized we wouldn't just shut down cases on them. Almost immediately there were tensions. I'd go out and visit and oh man it was tense. There was this idea that support just had to be in the valley because straight up the managers and folks working there didn't know there were technical people... anywhere else (this was before we had other islands of tech in the US).
I even bought it for a bit thinking I was going out to meet some high performing folks and found ... way not that.
It was amazing that they had (including some management) convinced themselves that stuff only happens in the valley and if they hadn't seen it they wouldn't have believed it was possible outside (and some did not, oh the excuses).... and that was just for a maintenance type task like tech support. (granted this was some high end stuff so it did take good people, but they're everywhere)