PACS developer here - I asked the same thing a few years ago when I started in pACS about automation. I was told it's the need to have someone to sue that holds back the automation, not so much the technology.
I can see an argument that if the company was sued then it could try to push the blame onto the software vendor, but surely that would be decided based on the contract between company and software vendor, which is usually defined by the software license.