There's also local inertia to get over.
The village next to ours complains about speeding despite having a 20 zone in the middle of it, at parish council meetings they discuss how they have been out with the community speed gun and people are still speeding and what should they do about these "youths" speeding through the village.
Given the village already has a major pinch point that reduces the traffic to one lane, I suggest why not a few speed bumps or a chicane or two. Oh no they say that won't work here.
It's because the worst speeders are the locals who also complain about the other people speeding, they want to have a moan but don't want to do anything about it.