I serve small business clients, and many small businesses depend on one key management application, that would be too expensive to change even if the replacement were free (which is unlikely).

In many cases, that application is Client Server, and based on an engine that is not available for Linux, or the publisher simply won't support it on Linux even thought the engine is available and works fine. Even with some regular LAN applications that don't care, tech support will hang up on you if they hear you have a Linux server on your network. Since all these managment applications include numerous "quirks", tech support is needed.

Just a week ago I got lambasted by an Act! consultant about how "Bill Gates won the war". By time I got to the site, he'd already gotten info about "unsupported" Samba config from Symantecs tech articles (Opportunistic Locking must be turned off for Win98, NT, 2000, and Samba). The immediate problem was just permissions which I fixed in a few minutes and he left happy with a copy of my smb.conf.

I go through this "unsupported" crap all the time, but it's slowly drifting to "We only support Red Hat". Same cop-out, different phrase.