There are two aspects to what you are saying.
First, there are delays, which are indeed difficult to tolerate. Second, there are refusals, which are significant and are unfortunately often poorly documented.
It should be said that refusals related to financial evidence, for instance, would be easy to modulate. The financial requirement could be modulated based on a laboratory research assistant contract, for example, or based on the applicants' potential income as Canadians.
International students in Canada have the option to work a few hours a week. That should be considered in analyses of their financial resources.