There are good reasons why someone might temporarily be breaking the speed limit, that are even accepted legal defences in some countries (if you have enough proof).
Biggest one is just merging / changing lanes. Often you have to go 10 or 20 over the limit to merge without impeding a lane of traffic. I sometimes see people stopping(!) at the end of a merging lane when there was a perfectly good gap they could have gotten by just speeding up. Trying to merge from a dead stop onto an 80kph+ road is more dangerous than going 90 fore sure.
Another one is on 2-lane roads. You catch up to a truck/lorry and see a gap. The gap is big enough to get the overtake done, but you instinctively go faster to make the whole thing less of a close call. Is society really helped if every truck has a 20-car queue behind it because people are afraid they'll get fined if they help traffic flow?
On a more general note, I agree that there needs to better enforcement. However, better enforcement to me includes removing all the sneaky money-making schemes you see in the wild. They put a speed limit sign on the wrong side of the road, behind bushes or behind street-side parking (often making the limit non-enforceable legally), put up a speed camera and cash in on people that won't defend themselves.
That shit has to stop, put those ressources on deadly country roads, in front of schools and other accident hotspots instead. While we're at it, do more preventative traffic stops. It's not right that blind grandma or psychotic grandson have to seriously hurt someone before anything happens.
Little anecdote here: I passed my driving exam despite going 30kph over the limit while overtaking a tractor. I just told the examiner that I was trained to leave the opposite lane asap, slowed down as soon as I noticed how fast I was going and there was no issue.