Temporarily, yes, and it often comes with the burden of providing for the migrant for the rest of their life.
the most effective way to end poverty long-term is to create conditions in which populations of impoverished nations fix their own problems on their own soil "over there".
Not to mention, if everyone could elect to move wherever they wanted: what % of the world's population would overwhelmingly choose West EU/US/Canada?
Even without the "burden of providing": Drive around Toronto and outlying areas and see, that even with Canada's still restrictive immigration policy, even across economic status, the idea that everything mixes into one cohesive society is laughably false.
Argument is for removing barriers, not for forcing people to go somewhere.
Charter cities are another option, but the argument that "we need to fix over there so don't let people move" is just perpetuating the status quo more than anything.