How long do they stay in the money chair?

I think it's an unfair advantage that they can only be knocked off the show during the third challenge level. They lose to the first challenger, but then they allowed to go back to the winners row and to wait on winner's row? They should be sent home with their winnings and replaced by the player who beat them. It seems to me that the early players have an advantage of being able to accumulate more money and then have the luxury and getting beaten but being able to remain on the show, and thus earn more money and not getting replaced. I also think that when the last segment occurs and one of the 4 players goes to the chair in a winner-take-all round, the player taken should be the one who answered the fewest questions in the interim. The show is too short for the highest scorer to be allowed to choose the person who goes in the chair.