I don't know if Epic is a private office nirvana for each of their employees, but to be fair, it does sound like the majority do have a private office. I only live in the area and hear stuff second- and third-hand, but I gather an increasing number of Epic employees are assigned to shared offices. The Boston Globe's glowing commentary on the campus concurs:
"Most employees have a private office; some share one with a colleague."
I've heard the same thing. From what I understand, the issue is that Epic is growing faster than buildings can be built. Regardless, while a shared office is worse than a private office, it's way better than almost any other option. I've worked in a shared office with a partition, a cubicle farm, and an open office, and the shared office was the best work environment by a huge margin.
"Most employees have a private office; some share one with a colleague."
https://www.bostonglobe.com/business/2015/07/28/epic-systems...