I see the issue as World Race Productions not having a first task near the AR22 start line to "separate the wheat from the chaff" as Phil has said earlier. If they had, probably the composition of the first flight would have been closer to the teams now remaining.
I disagree. The way I see it, most of the teams eliminated so far weren't inept continuously, they were pretty competitive people who ran into just one inconvenience that sealed their fate:
* The twins are done by facing the one challenge they were not ready to deal with
* Jessica & John were done for their bad luck and lack of judgment, after they had been racing consistently well
* Dave & Connor were leading the pack in spite of their injury and only had to withdraw out of medical concern
* Pam & Winnie were also leading in later legs but were done by what could only be considered a "brain fart"
I believe these four teams wold have had a chance at the million had they not tripped.