The tech specialists are all former skaters (in whatever discipline they competed) - it is a requirement. The tech controller is an ISU judge. I don't know why a skater would not want to be accurate in making calls as many of them can probably relate to being on the wrong end of a bad call sometime in their career. And anyone can make an honest mistake, which hopefully is caught by the tech controller. I have a problem with using judges in high level competitions like Worlds that come from countries without a strong program especially in pairs and dance.
As for all judges not being part of the "social scene" at major events anymore is mainly due to $$$$$. The ISU is not making the money it did years ago. It's a budgetary issue.