If you believe the OA serves no real purpose, I would say that either your lodge is not fulfilling its mission, or you aren't well informed about what the OA does in your council.
An active and thriving lodge provides a significant amount of service to the council, camps, and community, as well as financial support. At the National Order of the Arrow Conference last week, the new Chief Scout Executive addressed the attendees and threw around some statistics that indicated the OA provided over 1 million man-hours of service to councils and camps in 2011, and many more millions in direct financial contributions and materials. Many of these projects go beyond just setting up camp. Over the past three years my lodge has completed many lasting projects at the two camps it supports including gateways to both council rings, fencing around the waterfront, and a new waterfront tower.
Many lodges, including my own, support the cub program by running an Arrow of Light weekend for 2nd year webelos. It is held at the Boy Scout Camp and is run much like a day at camp, with the intent of promoting the camp to these webelos and getting them to camp the following year. This event is always a huge success.
In my opinion, the largest contribution the OA gives is real, hands-on leadership opportunities to youth. In this regard the OA is much different than a troop, crew, or any other Scouting program. In a well run lodge, the adults take a back seat - mentoring and coaching behind the scenes - while only the youth take the stage. There is no "troop committee" calling the shots. The boys run the budget, the finances, the program, the day to day operations of the lodge, as well as long range strategic planning. This is done with coaching and mentoring by adults.
A well run lodge supports the council and is aligned with the council's goals and priorities.
It is important to understand that Native American culture preservation is not part of the purpose or mission of the Order of the Arrow. If your lodge operates as if they are, they are not following the OA program. Ceremonies/Dance, etc. are used to augment the program. A well run ceremony is a very inspiring thing, whether you are at your first Pre-Ordeal ceremony or your hundredth. They help us be mindful of our purpose.
This is all not to say that there are lodges out there that are run more by adults, or that they are poorly managed and not following the program. That is a real shame to see. But many lodges across the country are integral to a successful council and camp operation.