It's not just like that in Asia. When I came to Canada from Argentina, I had just finished grade 3, and I was given a bunch of tests to see what my level was. In particular, I was tested at a Grade 9 level in Math, and I wasn't privately tutored or anything like that.
Of course, my parents could afford to send me to a good private school, where I worked very hard. Argentina as a whole did rather poorly on this test because those whose parents don't have money go to schools with no budget for anything and teachers that are on strike half the time.
That said, I never had any homework, and the school didn't filter incoming students with tests or whatever, anyone who could pay could get in. However, the work was rather hard. For example, in grade 3, one was expected to write 3-5 pages by hand for a 1-hour test. In Canada, I only started to see that kind of crunch in grade 10.