(International experience class does not apply to me)
Unlike countries such as France or Sweden that have naturalisation after X years (5 or 6) of legal residence, I understand that staying for a period of years does not automatically give any residency rights in Canada (which is similar to Australia, Singapore etc).
One needs to be above the CRS score cutoff to be able to compete with other applications for, and get, Permanent Resident status whether or not one is already in Canada (on say, a work permit). Work experience in Canada for 1-2 years appears to add some more points to CRS, but this is not a "guarantee" of getting a PR. The Provincial Nominee Program adds a lot of points as well, but it appears to be invite-only and its possible to never get a PNP, either. In general, average / median CRS scores of a cohort are getting better every year (meaning ever better qualified applicants). Please correct my assumptions if they are wrong.
So is it possible to move there on a Work Permit, but due to increasing age (despite increasing experience) and intensifying competition - never get enough CRS points or a PNP, and thus be 'permanently stuck' renewing Work Permits in Canada? What are the chances this happens?