Yes indeed, I think that a lot of folks underestimate the cost of doing a rotary run. The OY would easily cost as much to run as a steam locomotive, and you'd probably need at least 2 K-36s to push it. At charter rates, you'd be looking at $30K per day, just for the steam equipment. Add in all of the other personnel and equipment that would be needed to support the operation and it would be a very costly proposition.
I attended a rotary run back in 2011 on the White Pass & Yukon, and there were about 40 railroad people involved each day....and 3 trains, including the rotary and its 2 steam pushers, plus two diesel-powered work trains carrying water, fuel, bulldozers and backhoes up the mountain. The White Pass folks did that run primarily for crew training....and because they could. They have a VERY lucrative tourist business from the cruise ships, that enables them to occasionally do things like that.
I would love to see a rotary run on the C&TS, but the trick is figuring out how to fund it. The risks (lack of snow, too much snow, equipment breakdowns) and the costs are such that no charter operator would be likely to attempt it. More likely would be some sort of sponsorship, either from corporate entities, or a grass-roots fund-raiser, in which folks who want to see it could contribute, and if the goal is reached, it happens. If not, everyone gets their money back and it doesn't.
Come up with a way to pay for it, and it may become a reality.
/Kevin