This started as an IDPA vs USPSA thread and has gone so far off the track it is unbelievable but I need to answer the above.
I have seen shooters that cross over into all sports. I have found the fastest USPSA shooters honed their skills shooting steel or pins. The speed and accuracy needed to be successful in those sports one round at a time make them take charge in USPSA after they learn the sport.
Take any of the top USPSA shooters in any division and ask them if they shoot Steel Challenge or Bianchi.
Pete, you need to go to the Wallum Lake Walls of Steel match and see what it is like to shoot the 25 plus plates consistently fast and accurate. It is not a 21round mag spray and pray fest it is a 10 round mag max.
Top shooters in any sport will always be top shooters. Many very talented shooters contribute here but there is no one sport that can state their shooters are as you stated, the most skilled.
One shooter I can think of that is basically a steel shooter shot a Harvard match with no sights on his gun and finished in the top two or three.