ennobee said:snip snip
I dunno, there were French television shows, both native and translated. Not that many, I grant you that but they existed, things like Fantomas, Vidock, les Brigades du Tigre. That's at least enough to show there was a market and it could have gone that way.
Maybe it's just because of the creators? In France (sorry I'll say France to refer to Franco-belgian comics, please don't hit me) it produced a lasting legacy because there were so many geniuses.
For example, you had a pre-WWI genre with stuff like Bécassine, really for kids. Then it moved to the more "classic" stuff like Tintin, which defined a lot of the codes, both graphically and narratively. We can see the huge impact of Hergé on this. Post-war you had a continuation of that, touching on more mature themes in the constraints of the kid oriented genre, with Buck Danny or Rahan.
I would think a big turning point would be with Franquin, where he put forward adult oriented comics with his Idées Noires (1977) which was not adult because it was sexual or violent but because, well, if you're giving the Idées Noires to your kids, you're a sick, sick man.
So, thanks to Hergé, Franquin, and the team at les Humanoïdes Associés later, you have your turning points.
Again, I'm by no mean a comics historian and I probably missed a shitload of stuff. Do correct me if needed!