That is easy to say, but extremely difficult to do. In MT the FWP has a bufferzone for domestics. They have to be 15/20/25 miles (I don't know exactly) from any sheep reintroduction. The young bighorns like to travel sometimes looking for love.
In one place where they were putting BH, there was a domestic sheep operation. 5 or 10 thousand sheep. They heard them 60 or so miles from summer range to winter range. They were willing to work with the FWP as best they could. But it's been a family ranching operation since the late 1800's and it is the livelihood of multiple families. So really the only option to remove the domestic sheep would be to buy their land and sheep for multiple millions.
Look at all the land the RMEF has secured for wildlife of all kinds. They only have a few hundred thousand members, and they have several million acres set aside that will never have a house or strip mall built on it. Maybe another organization could take up the cause of securing funding, for when a sheep ranch comes on the market.