B2B Soft interview questions

HR contacted me and arranged an interview. On the call she explained the position but as well asked questions about my past experience. It was a basic pre-screening process. Once she felt I was a good fit she arranged an interview time & date. Met with the manager of the sales team and he asked questions about my current job and past experiences. He briefed me over the job and asked if I was able to satisfy sales quota.

I had a total of 4 interviews, the 1st with HR, the 2nd with a manager, the 3rd with a VP and the 4th with a VP and the CTO. Each conversation was a series of questions regarding project management, no behavioral or situational questions, just process. I found it very unprofessional that after participating in 4 interviews I received no follow up as to whether I would receive an offer or if the position was offered to another candidate. If it had been 1-2 interviews I would have expected just a discontinuation of communication, however after 4 interviews it’s completely unprofessional.