What will happen is what happens with all decline in revenue...they will just ask the voters for more tax money and they will give it to them. During the last decline they let our roads go so bad people had no choice but to increase the taxes....then they did the same thing with our parks, they refused to mow the grass but once every two weeks and took other amenities away which ultimately lead them to ask the voters to increase taxes...which they did. Same will happen with any decline in traffic fines, they'll let people sit for hours waiting for cops until they give them what they want.
As far as Bitcoin or cypto is concerned we just have to look at this site as an example that it's no better than the system we currently have in place. It's even worse if you consider the number of spammers and scammers taking off with hundred of thousands of dollars each and every day....this would have came to a halt a long, long time ago in the real world of things.