It is much easier for Canadian companies to fire employees. In Europe, the labour laws are so strong that if you are hired on somewhere, it can be very hard to fire you, even if the company is doing badly. Because of that, it's hard to get hired and the companies cheat by hiring people on contracts or using manpower agencies. Once people are hired, they sometimes stay in the same job forever, even if they don't really like it because they are afraid it will be hard for them to get another job.
In Canada, the employee doesn't have that many rights. The company is doing badly and they send you home with 1 day notice on unpaid vacation. "Sorry buddy, times are tough, we'll call you when there's work." You are free to look for another job while you wait for the call, unless of course if you are on a work permit, then you'd have to get it changed before you take another job. You do not know if they will call you back in a week or in 2 months. They could theoretically call you back in 2 months, have you work for a day and then send you back on vacation. This is referred to as a temporary lay-off. They can also cut your hours any time they feel like or they can just lay you off permanently but then they need to pay you your notice. It's more likely that they'll use temporary lay-off because if you have another job by the time they call you to come back, they never have to pay you for your notice period.
Because it's so easy to get rid of people, it's also easy to get another job. The employer knows that if he doesn't like you or your work or he doesn't need you anymore, he can get rid of you easily so he has little to lose by hiring you. This makes the job market very fast. You can have a job today, unemployed tomorrow, new job next week.
It's actually considered good for your CV in Canada if you have changed jobs every 3-5 years. That means you've stayed long enough to gain experience but not long enough to get lazy. If you'd stayed in the same job very long, it might be seen as a sign of being lazy, unmotivated, afraid to try new things, afraid of challenges etc.