That's exactly my point: a dev working for Facebook in Hungary will probably make decent money but it will still be a fraction of what he could be making in the US..
The rough estimates I’ve seen are: $100k USD in MPK becomes about 85k CAD. But also I think they just don’t fill as senior roles in Canada so the upper limit is lower. If you want to make more money, I think it’s worth a shot -- if the offer is bad, you don’t have to take it.