When the two factors merge, they can be very compelling. The surest way to escape Canada's tax system is to become a non-resident. But this is not as easy as it sounds. In addition to physically moving out of Canada, you must also cut your social and economic ties to Canada. The major difficulty is that many people who consider leaving Canada never really want to make the total break.
Retirees have an additional problem.
If you are willing to submit the facts to Revenue Canada, they will make a residency determination. But their opinion is only as good as your statement of the facts. If you happen to omit a fact that Revenue Canada later considers material, they will have no compunctions about changing their mind. There are also a number of misconceptions about becoming a non-resident. One of them is that you can leave Canada, escape its tax system, and become a sort of free-floating citizen of the world, avoiding the tax regime of any country.