IMO, the road to Indy was rerouted in the mid to late 70's. You saw fewer and fewer short track drivers advance to the Championship Trail in the 70's until by the late 70's it was pretty much done. Duane "Pancho's" Carter is the last USAC Sprint Car champion that I can think of to advance to the Indy Cars and have a full season ride.

Again, IMO the "new" Silver Crown cars were an attempt to provide a transition car to enable a driver to more easily adapt from the short tracks to the bigger stock car tracks and their speed. The idea and design was driven by the stock car world, not the IRL or Indycar.

Short tracks teach a driver to be aggressive and how to drive a loose race car, two things that are pretty undesirable in today's "fuel conservation" neutral setup Indy cars. Like it or not (and I don't!) I don't believe you will ever see short track drivers as regular participants at Indianapolis.