My understanding is that the real problem is twofold: First, some proprietary software only supports a subset of distributions. Debian is rarely on that list.

My understanding is that the real problem is twofold: First, some proprietary software only supports a subset of distributions. Debian is rarely on that list. RHEL, for some time, has been a safe default. Second, IT organizations only want to support one distribution when at all possible.. As such, RHEL and CentOS made a lot of sense. RHEL and Debian means twice the work. That said, it's going to have to change. $349 for every 2 VMWare images (as I understand it) plus $2499 for every 2 processor sockets adds up.