so I just read that whole thread (minus the french bits), so I'm just gonna add a couple of points-
Polyandry does exist in nature, especially in birds, where the females need males to help collect food etc, so they have alpha and beata males. This seems to occur in the human race as well, when many women have kinds wth a 'Romeo' type, then find some guy to help raise their children, thus they have gotten the best genes. Obviously its not the polyandry everyone else was thinking of, but it is still a form of it.
Secondly, there are overall more females than males in humans, but there are actually more males born (or in some cases equal), than females, its just males have a shorter lifespan. So if men want to have 4 wives when they are 80, then go for it, because at that point there is enough 80 yr old women for them, but otherwise, that dynamic does not work.
and using the site:
AFROL Gender Profile - Algeria
heres some specific stats for Algeria (yayness)
Sex ratio: at birth: 1,04 male(s)/female
under 15 years: 1,04 male(s)/female
15-64 years: 1,02 male(s)/female
65 years and over: 0,86 male(s)/female
total population: 1,02 male(s)/female (2000 est.)
showing that overall, its currently not possible that every man gets even one wife - let alone those who take two. I always joke thats why my partner had to out-source for me :P