I actually think its a really good reason why it often goes wrong in the sense that most governmental agencies always think they need to somehow customize to their unique needs.

I have seen this many many times when dealing with governmental contracts.

Another issue is the way these procurement offers are made. They are basically forcing the bidders to define their way out of every issue they might encounter just to make sure they don't suddenly get caught with having to do the work after some huge issue and no budget to do it with.

So instead a lot of the proposal is about defining the scope of the projects but in such a way that most of the budget is a buffer for when the project go wrong.

In most cases these systems already exist and could be much easier build with off the shelf based software. But because government think their needs are unique they end up building themselves.

In Sweden the police were able to implement a new system without many issues exactly because they used existing system rather than trying to invent their own.

In Denmark they thought they needed their own and are paying the price with a version they had to scrape.