You weren't even allowed to touch the infrastructural M code. Mostly, you worked on superficial or peripheral M code, or on the GUI in VB6. I heard rumors of a GUI modernization team, but never saw any direct evidence of it.
It was a result of the iron grip of the top management. They didn't want to yield control of the company to the people actually running it. You were expected to use your expertise to do what you were told to do, in the best way you could, while still remaining completely within your lane.
After the 6 months of training, I gave it a year to read the character of the company, and then another 6 months to soak some potentially major family health care costs with that sweet insurance plan, then spent 4 months job hunting. It was the best employer-offered health insurance plan I ever had.
But make no mistake. Companies like Epic are why health care costs in the US are huge and growing. Epic never refactors anything that still works well enough to hold together with some expensive human labor. It is a technology company that runs on well-trained people instead of well-designed code and processes.
Some functional areas use Hadoop and SQL now. New server development can be done in VisualStudio using Typescript (which gets converted to M).
There are automated tools to set and verify OS parameters.
Most new installs are Linux now. No one uses VMS today. HP-UX and Solaris will be out of use in a couple years. InterSystems licensing is why people continue to use AIX (you have to buy new licenses to switch from AIX to Linux).
Since I was more in their systems department I had limited opportunity to observe their archaic superstitions about code structure, but the short introduction course to M they provided confirmed that most current and new employees were willing to accept that certain control flow tools or function structures were dangerous because they were necessarily slower than something that made sense in hand assembly programming, since there had obviously been no developments in compiler optimization since M was designed (in the good old days, before C existed).