I guess the perspective towards global migration being done not just by millionaires but even the ordinary people have no direct relationship to the existence of Bitcoin to make them change their way on not migrating because people do have different desires in life and reasons why they migrate into different places. Mostly reasons are because they were seeking for boundless opportunities that can be found in other places.
Well, there might be reason related to Bitcoin why other people will do migration it is duly because some countries prohibit the usage and existence of cryptocurrencies making people who do really want to use it will get into other countries where it is allowed to be able to use it freely. But that would be an example on how Bitcoin cannot affect a people's decision on just staying up in a single place and never get away. It is because Bitcoin have nothing to do on why people decide to migrate it is duly to the reason that people just have their own reasons for migration and that's it.