The Mark USA interview questions

Went through three rounds of interviews including two Skype calls lasting about an hour and a phone call going over an evaluation article. The first Skype interview was with one upper management person that went over standard questions. The second Skype interview was with the same upper management person and two additional people, including one who would have been my direct supervisor. I thought it was strange that the potential direct supervisor did not ask me that many questions whereas the other two interviewers did. The last round was a phone call where the interviewers gave me thirty minutes to read an evaluation findings article. I was then asked for my thoughts and critiques of it. The interview process was a bit tedious and very long. It finally ended with a reference check and a verbal offer over the phone. I wasn't very satisfied with the salary they offered as it was on the very low end of their pay range. After I asked through email for a written offer to see it in more detail, they refused on the basis of me not accepting the offer via a verbal confirmation. I gave them a bottom line salary and they have not responded to that email. They have ghosted me but I am certain that I have dodged a bullet.