Interesting, but I think you're off the mark ultimately.
Things like changing currency, a new (better) measurement system, different laws - those are easy. A hassle, to be certain, but far from a real prevention from moving.
Learning a new language should not stop people from moving there either - but that's a personal opinion, and I've also never done it myself. A challenge, but I think it would be a good challenge - the kind you'd like to defeat.
Changing employers does suck, but can be a great thing.
Culture shock - eh. I think your example is a poor one - an American in Djibouti or Iran would be a much more extreme culture shock than Canada or most of Europe. And in that case, just like your state scenario: don't go there, go somewhere else.
In Canada, I can assure you we do not bribe our police. We also have many of the same laws, our currency is practically identical in value, and so on and so forth.
Immigration laws are definitely a problem. But, again: there's tons of other countries, just don't go there. Canada, too, has rather relaxed immigration laws.
And, as for state to state, many of the same rules still apply, just to a lesser degree. Culture shock can certainly occur from city to city and state to state - and that includes the bribing of police officers.
In all, I think you are right, but the reality of the situation is much less severe than you think. It's true that getting into a new country is a challenge - but it is in no way an unacceptable option.