Now, whether in the coal-rich regions of Shanxi Province, the steel mills of the northern industrial heartland, or the airlines flying overhead, it is often China’s state-run companies that are on the march.

As the Chinese government has grown richer — and more worried about sustaining its high-octane growth — it has pumped public money into companies that it expects to upgrade the industrial base and employ more people. The beneficiaries are state-owned interests that many analysts had assumed would gradually wither away in the face of private-sector competition.