The "flow of green" thing doesn't work for a couple reasons. One, imagine one driver doing the speed limit catching every green light. Now imagine, 2 blocks back, there's another car doing the speed limit, but they're catching reds because they're behind the target car. So they are now incentivised to speed to catch up to the car that is reaping the benefit, so they too, can reap the benefit.

But then you get local businesses saying that if someone never has to stop, what they pay extra to be on a corner and run advertisements on billboards or other signage isn't paying off because people aren't being stopped there. They might as well pay less to not be on the corner. By letting traffic flow free, people are getting more miles out of their tyres and brake pads, so your auto body shops are losing money, too. On top of that, ICE engines use more gas when they have to stop and start, which is why most people can go, at most, 1-2 lights before stopping, because your local city government doesn't think you're paying enough for petrol.