Is the client (state-owned enterprise/public institution) completely free from risk? No.

The甲方 only refrains from laying people off, which doesn't mean they won't force you into long-term assignments in Africa or India, making you quit. Or they might establish a purely market-oriented subsidiary and transfer your entire department into it. A few years later, the subsidiary struggles and shuts down, leading to collective layoffs. Such things do happen. It's just that they're relatively more stable compared to private enterprises and foreign companies.

In private enterprises, people tend to job-hop every few years; in foreign companies, there are annual layoff lists. Compared to these, the甲方 is relatively more stable.