Just as you've stated above,the reason why there's been a decline in bitcoin mining is probably due to the fact that the miners no longer see it to be any profitable in relation to the present price..
And from the aforementioned countries,probably Venezuela and Ukraine could be a good bet,and miners could possibly make ample profits..

But with the US and Canada that I highlighted,i doubt if anyone would be spurred on/encouraged to mine over there considering they are bound to make little or nothing from it
As the price of mining one bitcoin is almost equivalent to the price of the bitcoin itself