It's all a matter of budgeting. CIC is ridiculously understaffed. They have 5000 employees in general with many case processing agents working on temporary contracts. Yet, they manage to issue 250.000 immigrant visas yearly. USCIS has 19000 employees, and although the USA has 10 times as large population as Canada's, green card and citizenship applications are processed in less than 6 months on American soil.