The goal of the design should be to lift the required payload to the specified orbit as efficiently as possible. Unfortunately, it appears that isn't NASA's goal. Instead, it seems NASA is more interested in maximizing the number of employees needed to operate the Ares which is the exact opposite of efficiency. The end result is likely to be a vehicle that's extremely expensive to operate. It really begs the question of why they're developing it in the first place. Personally, their reasons for not using an ELV are dubious, IMO.

If you go to Orbital Sciences or Boeing and ask them how much for a launch of a given payload into a given orbit they can give you a ballpark price. If you give them all the details of when you want to do it, exactly what orbit, whether any special payload handling is needed etc etc etc then they can come up with a contract for the exact price.

All of those boosters exist, so the R&D costs are already sunk. They know what it costs to build another one and it takes a known (and very small, compared to NASA) number of personnel to launch one. That makes the costs more predictable. For the Ares, none of the numbers are known and the hardware design isn't even finished. Unless NASA uses tax dollars to artifically lower the launch cost through heavy subsidizies (as they did for commercial Shuttle launches in the 1980s before the practice was banned), I doubt anyone in their right mind would consider using an Ares I booster to launch their payload.