That's what happens when you have depth and a 6-3-3 team format. If Dowell was sorely needed, then I bet she would still be doing TF, but the other gymnasts on the team can cover UB. With 6-3-3, not having all 6 gymnasts compete in TF is pretty normal and as much as it sucks to have one less team member, having five member teams make much more since with this TF format in that it better ensures all gymnasts are used. Plus, I'm sure Marta wants to avoid a Mattie Larson situation where they use her because they felt bad and thought she could redeem herself only to have her lose the gold. With depth, the Soviets were notorious for casting great gymnasts aside when they were no longer needed.
Unless you're saying Dowell is completely out of the team, which I don't think is the case. She competed in Prelims, so she'll get a medal and official recognition as a member of the 6 member team.
As for Marta's atmosphere and death camps, I think most people agree with you, and she was heavily criticized in 2004 and 2008 where it was clear the majority of the team was really beat up and tired by the time the Olympics rolled around. I thought she cooled it by 2011 2 where the gymnasts looked happy and healthy mentally and physically. But I do see the heaviness creeping back with every gymnast here other than Simone who seems to have a very healthy perspective on life thanks to her family and coaching team.