I know a friend of mine who got PR as an assistant manager from Subway last year. He was actually a doctor from his home country. He busted his ass, worked his way though difficulty, did two jobs and volunteered his time at a community clinic too. Now he got into medical residency. He could never have gotten into residency if he didnt have the PR. Would you call him unskilled ?
EE give everyone fair chance of PR, especially those who are in Canada as their jobs are highly scrutinized. Speaking of people using lower skill job for PR, its very easy if you are outside canada. You can become manager at your friends retail store, and file for PR. Infact you won't even have to be paid $4000 a months. Even $200 salary would suffice. Now that is a misuse.