Makes sense, and I know driving in france I've felt the same. I also know driving in Canada our speed limits often cater to some lowest common denominator, where anyone driving the limit is going dangerously slow (I'm thinking of certain country roads) and inevitably has a long line of angry people following them.

I've heard before about setting speed limits using percentile studies of people driving on the road, which in the absence of some specific safety concern (which then needs engineering like narrowing the road or adding turns) makes the most sense.

I also wish there was more of a culture of pulling over if you don't want to drive at the flow speed. If I want a leisurely drive and see someone rapidly coming up behind me, I'll happily pull over and let them pass. There seem to be these sociopaths or self-righteous jerks who will happily drive 5km/h under the speed limit with 20 cars behind them. This is way more dangerous than speeding and should be treated as such. If you just want to drive slowly, why would you want the stress or a bunch of angry drivers behind you.

I think the concept of a “speed limit” is part of the problem. On controlled-access roads, I think it would be better for the posted speed to be advisory and, instead, train drivers to think of driving too slow for your lane as being just as dangerous as speeding because, in a moving group of cars, you want to be as close to 0mph relative to the other cars as is feasible.