They don't have the capability nor the technical knowledge of setting up mining grids. This might sound a conspiracy to many here but I believe India is involved here.
So what's this secret technical knowledge that's involved in setting a mining farm?
If you have the knowledge of setting up a datacenter then you have the knowledge of setting up a bitcoin mining farm when it comes to technicals.
You don't need the help of a country when you do this on a large scale because if you place a +million orders with Bitmain you can talk to them on expertise in setting things up. Also, no offense, but India has as much expertise in this field as Vanuatu!
Besides, why would be India interested in Bhutan using electricity to mine when instead they could simply force them to sell all that electricity they have nothing to do with cheap to India itself?
But the fact is that Bhutan has a very small landmass. So they can't build a huge heavy engineering project which can provide employment to their citizens.
Bhutan is the size of Switzerland and Taiwan, just as you can build a hundred dams or smelters for whatever you mine you can build everything else.