Having first hand experience in organizing the unionization of my employer and obtaining an initial contract I am not surprised by the length of time involved.Obtaining an initial union contract takes a long time, particularly if the employer wants to continue to resist and fight. Thus hoping their employees will give up and vote out the union thereby negating the original vote. It is even more difficult in the right to work states.
Our first contract took over 18 months to obtain, after the ratifying vote, and although there was resistance to parts of the contract the employer accepted the presence of the union and did not try for desertification.