The problem lies in the quality of talent on a track to track basis. Lets face it, most tracks in the midwest just don't have loaded fields that places like Kokomo or Eldora have. There are WAY WAY more "have-nots" than "haves" in local racing.

If you have a field of top tier equipment and talent, then you really don't need any kind of inversion system and drivers should be able to earn their way forward all night.

Now if we go to Joe Blow Speedway and they have 20 cars, but only 5 real contenders, then you need an inversion system. Problem with inversions is that drivers lose their incentive to "RACE" in the heats. Noone pays heat races anymore... and they should.

The answer is, there is no universal answer. It will always be something that changes based on the circumstances of each individual track.