>Do you think humans will be able to be effective supervisors or "review-engineers" of LLMs without hands-on coding experience of their own? And if not, how will they get it?

The wont. Instead either AI will improve significantly or (my bet) average code will deteriorate, as AI training increasingly eats AI slop, which includes AI code slop, and devs lose basic competencies and become glorified semi-ignorant managers for AI agents.

CS degree decline through to people just handing in AI work, will further ensure they don't even known the basics after graduating to begin with.