That's actually really easy:

1. be government agency

2. pay 30-70% less than private sector companies would for a similar position

3. receive applicants that are 30-70% less competent

Bonus:

- have 30+ year old systems nobody understands anymore because the team behind them has been dead/retired for a decade

- have hiring process handled entirely by out of touch suits

- have a revolving door of motivated soon-to-be burnouts mopping up the mess behind the aforementioned regular employees