How would a local government make the switch from Windows to Ubuntu?

Your question is going about things the wrong way. It’s like saying “Here are the wheels I want”. Now what kind of car will fit them?

First you have to look at the size of your municipality. How many employees what application software do you need?

For example you might need water & sewage billing software. What operating systems and hardware does it require to run?

You might need payroll and benefits software. What operating systems and hardware does it require to run?

You might need fixed assets, inventory control, equipment preventative maintenance and work order software. What operating systems and hardware do they require to run?

About the only thing I see as Linux likely only I see for Municipality is the website software. For all the rest of the application software I imagine your options are 95%+ Windows only.

When you are paying $100 for Windows on a client PC you are often spending $1000 per seat to run the application software which costs $100,000 plus for the core on the server(s). But writing the software from the ground up on a different OS (like Linux or Windows) can cost over $1 million.

Let’s not forget any city > 30 years old may have IBM S/390 mainframes and AS/400 minicomputers running their mission critical applications. They may have Windows PC clients (using terminal emulators) that can be converted to Linux PC clients on a department by department basis.

Don’t restrict yourself to the “When all you have is a hammer everything looks like a nail” approach.