"Why can't the LSR world correlate their classes with other sports racing bodies (SCCA, IMSA, etc.) and retire the roadster-hotrod-studebaker classes that on one hand, dilute the potential of modern participation and on the other hand marginalize the participation of modern types of racing."
hmm...blue,
since there is no other sport like this, how could you possibly correlate the classes? Those that you refer to are worlds apart from this sport.
What possible reason could you suggest that would motivate any of these proven racers, the very fastest in what they chose to do, to dilute the experiences, the accomplishments, the satisfaction, simply to encourage some others to participate? The only encouragement most sportsmen need is to see where the bar is set, and imagine being able to raise it a notch.
While all are welcome, this organization and events are here for a very specific purpose. This sport is growing without compromising its' origins or principles.
I would suggest that grousing about the current class structure only shows that there are some folks that want to participate, but might not be able to cut the mustard
You dont have to try to compete in those classes that you feel are behind the times, especially if it would be fruitless to even attempt to do so.
Get a rule book, and build something competitive. Or beat your head against a brick wall.
Whichever sound best to you