Not at all my experience of consulting companies. What I saw was that they were very useful training pipelines for juniors.

The companies would staff projects with a mix of seniors and juniors. Seniors to get started fast, in the right direction, and actually guarantee the delivery; juniors to keep the costs lower and to have a pipeline of new people. Hands-on from day 1, sitting with seniors in a project with clear timelines and deliverables, with projects and technologies changing regularly, tended to level up the newcomers fast.

This was in small to midsize (50-500) consulting companies where the projects did not come via CEOs being buddies with others.