I was really excited about this position and had history with the company. After 4 long interviews with multiple people on each, they ghosted me. It is completely reasonable for them to choose another candidate. It is completely reasonable to change the scope of work. It is reasonable to not proceed with the job. It is not reasonable for them to ghost a person after 4 interview rounds. Please, please, please, just let a person know you are going in a different direction.