The government doesn't pay low salaries to coders, (remember, all they really need are CRUD apps. This isn't rocket science), its just HORRIBLE at hiring.
Rather than leaving any hiring decision to anyone who knows the issue at hand, hiring is done based on a process which is optimized to be legally unimpeachable. When government succeeds, nobody gets credit, but when they get sued, its cover your ass time. This is why ALL government processes, including hiring, are first and foremost about CYA.
I've been able to witness some of this in the State of California. This system is designed to try to prevent the government from overspending on software. They can always point to a public RFP and open bids if anyone objects. However, it is not designed to produce the best value for the state.
First the RFP has to be written, which itself is a very political process and may have been initiated by a contractor/sales-person convincing someone they need the software or process in question. They'll often help write the RFP if you let them. These RFPs are often signed off on by non-technical people who are not qualified to really understand the technical details.
Then the state has to get multiple bids. Sometimes the RFP is written so specifically that many options are excluded. For example, I've seen an RFP that required the state pay for the software. The way it was worded excluded an OSS contracting company from providing support for a Linux solution. A more public example is the LA School District looking for computers for their students. They are required to support both a keyboard and touch, which is prime market for Windows Surface devices. It could theoretically go to something like an iPad, but it makes it very hard for laptop makers to compete.
Finally the state is required to take the lowest bid that meets the requirements of the RFP. To reject a bid the state has to show that it does not meet the requirements. They can't simply take something that is better value, they have to take the cheapest solution that meets the minimum requirements.
Rather than leaving any hiring decision to anyone who knows the issue at hand, hiring is done based on a process which is optimized to be legally unimpeachable. When government succeeds, nobody gets credit, but when they get sued, its cover your ass time. This is why ALL government processes, including hiring, are first and foremost about CYA.