I doubt it's just red tape. More likely there is invested capital that has to be EOL, and they wrap up all the changes across the stack in one place. Counterfeiting is sexy, so it's the excuse. But really it's a calculation based on depreciation and lifecycle management.

Seems like a bit of a losing game to try to fight counterfeiters on a 15+ year cycle. Who knows what home printing technology will look like in 10 years? Even 5 years from now is hazy. It's already the case that home laser printers can make some very convincing forgeries if you can track down a reasonably similar type of paper and defeat the currency detection firmware.