Actually ST electronics strategy is to keep the management levels as permanent. They can continue to manage and lead projects. While keeping the workers below as temp ones
Because workers come and go anyway. The only way you can be considered perm in ST is to be promoted to at least a manager level from your individual contributor level.

This is the same strategy with Accenture's division which deals with govt projects. But they are abit better, they do promote people from the bottom up. But just very rarely. Bottom people are hired directly as perm positions and their career growth is accounted for. Unlike ST you chiong so many years also never convert to perm, much less career progression.