It's often not a choice if you do not meet the countries requirements which are generally: be wealthy, have a higher degree and already have secured a job, or b

It's often not a choice if you do not meet the countries requirements which are generally: be wealthy, have a higher degree and already have secured a job, or be married to a citizen/permanent resident. As another comment mentioned open borders would make it a choice. A good test case is looking at movement within European countries that allow freedom of movement for other European citizens. I'm sure some people have moved to Andorra, Gilbratar, Liechtenstein, etc. for lower taxes but probably at a lower rate than people moving to places for employment opportunities.