I would ask anyone wondering "Why" to ask RMEF about the change. I did.
Cost to attendees is the biggest reason of changing to a different TAC companion event. Park City is an amazing resort, in many respects, if "resorts" are your thing. The term "amazing" also applies to Park City's cost and to their ability to keep everyone in the resort areas. There just isn't a lot to do other than "resort" activities.
RMEF wanted to keep it with a TAC event, so that doesn't leave may options. TAC calendar/events here -
https://totalarcherychallenge.com/
RMEF wanted a lower cost venue, as this Mountain Fest is a rank and file, volunteer, and member event. Big Sky, even with its surrounding Yellowstone Club and Moonlight Basin, is a lower cost locale than Park City, both to attendees and to RMEF.
Those members surveyed stated they would like options that did not require expensive hotels, such as campgrounds, etc. They also wanted to have activities outside the "resort" perimeter, something much more accessible at Big Sky and the surrounding area than can be found at Park City.
So, it makes sense to RMEF. It makes sense to the many attendees who don't want a $400+ hotel with $40 lunches. It makes sense to have it at a TAC events, as many of the Mountain Fest attendees like to shoot the courses and many TAC attendees are hunters who like what RMEF's event brings to a TAC event.
Like every new venue, I am sure there will be some hiccups. Always are. But, it will be a lower cost to attendees and give them many other off-resort activities to look into.
As someone who has attended the TAC events in Park City for years and the same in Big Sky, I think it will be a favored change by the average RMEF member who makes up the overwhelming majority of attendees at RMEF Mountain Fest. This is not a high-dollar fund raising event for RMEF. This is an opportunity for their members and volunteers to come together and have a good time.
I look foward to it. I'll be with our local committee at the RMEF booth most days. Like all years at Big Sky, I'll be giving away 500 Dilly bars to the first kids who show up.