As part of a very long term project I built exactly what the article says doesn't exist - a way to track onboarding and offboarding in a single system. One reason why it was a long term project is that it took that long for the systems and departments to catch up and buy into central tracking.
My system passed every internal, external, and federal audit. It is still running five years after I left the company. I was hired back as a consultant to integrate the parent data when the company was purchased because it worked so darn well.
What does it take? It takes C level buy in and endorsement to build and maintain. It takes the ability to get user data out of existing systems to track accounts. It requires a way for supervisors to request the access specific to their needs. It needs to get current and accurate HR data for MACD (move-add-change-delete) processes. It has to be linked with some sort of tracking application such as a ticketing system so there's accountability and tracking.
It can be done. It has been done. It's not an off the shelf solution and it isn't something that can be done in a month. It's hard work, it requires dedication to keeping it current with new systems, and it's worth every minute and penny spent.