Would you though? As somebody else pointed out it could be a good public works/job creation program. You could probably put 4-5 people to work cleaning up a year for less than 1 cop. I’m kind of making up numbers here but I feel like that can’t be too far off what with salary, pension, equipment, etc.
A few hundred people dedicated to taking care of litter would likely make a difference anywhere. You can get that for far less than $6 billion. You could pay 1000 people $1000/day to do it and you’d be at $365mill.
This works best when you pair it with promoting personal responsibility, otherwise you have to be careful it doesn't lead to the mindset of "I can throw this on the ground because it's somebody else's job to pick it up."
China does it well. You can't get unemployment benefit, but if you can turn up for work sober every day and are prepared to do menial work, you are guaranteed a job.
Chinese cities are clean and tidy, not because people don't litter - they litter much worse than Americans or Europeans, from what I've seen - but because someone is paid to clean up the litter.