It takes years for the Feds to roll out just about anything in a large agency. Computers, radios, etc. take time to go through RFP/RFQ. to selection and funding, manufacturing and shipping, to roll out and training. Don't forget that all the old stuff has to be returned to a central collection facility, inventoried, and then surplussed off.
I worked for a Federal agency that required every employee to update their photograph on their credentials every 5 years. One of my associates hadn't had a new photo in nearly 15 years from his initial date of hire, thanks to issues such as a lack of film, the transition from film to digital, software issues, timing, etc.