What?! I experienced this vastly differently. I drove from Dover to Lands' End and back this year, and the route was absolutely riddled with speed cams, compared to the Netherlands.
When they were first being installed, drivers got all whiny and said it wasn't fair. They were being tricked and local authorities were using them to raise cash rather than enforce speed limits. Cameras were placed where speeding was very common, and councils were supposedly hiding them behind foliage to catch as many people as possible. If they were really about stopping speeding, shouldn't they be visible?
Basically, drivers didn't want to have to obey the speed limit all the time (God forbid!). But they could just about put up with being forced to obey the limit where it was particularly dangerous. So to mollify the car lobby a rule was introduced that the cameras had to be highly visible.
It's surprising just how many people will continue to speed past these very visible cameras.