First, I would like to say that as a new member to the forum here have greatly enjoyed the many topics and conversations that I have read so far and have already learned a great deal.

As to the topic at hand; as some one who has had both Lloyd Clark with the IJA style of jousting and and Shane Adams with the American style of jousting perform at a medieval festival I was a part of, I think there is a place for both styles. Both styles have some very heavy hitting at times and both were very enjoyable to watch. As a member of a small historical group I prefer the more historically accurate jousting myself; however, in all the faires and festivals I have been to or been a part of, 95% of the people who attend are there to see the action not the historical accuracy.
I helped Lloyd at the IJA tourney in Michigan and the crowds that were there loved what they saw for the most part. There were some who felt it was fake because of the tipped lances that were used; but those people came off to me as the same people who would be disappointed at the NASCAR race if there was no crash.

I personally feel that the answer is to have both types of jousting at a tournament. By combining the appeal and strengths of both styles you would draw from a larger fan base and present a better product.
Would that make jousting a main stream sport? I don't know, but I think it would give it the best chance at succeeding.