In a stage like this, you're going to see a lot of sprinters and other non-climbers drop off the back and sometimes even drop out of the race.
In no other sport do you have teams that lose players and are unable to add them back. If you lose a soccer player to injury, you can add one in his stead. If you have to pull out a fielder in baseball, you can substitute another player.
But in cycling, the teams are whittled down from a start count of nine riders. It's pretty severe.
By the way, at today's start of Stage 8, no team had lost more than one rider. When we see the figures later tonight and tomorrow morning, this WILL NOT be the case. Team CSC has had some bad luck as have a few other teams.
I would guess that many teams are down to 7 riders after all the dust settles.